REESE  LIBRARY 


1    UN  I VE  RSITY  OF  CALI FORNIA;  '-I 


<iAcce^sion  No.       83593.   Class  No . 

W  «.■    .•••'■■■  •  •-  ■'■■■     T 


/  (>() 


BACTERIOLOGY. 


APPLIED  TO  THK 


CANNING  AND  PRESERVING 


.OF. 


FOOD    PRODUCTS 


EDWARD  W.  DUCKWALL 


Published  by 

THE     TRADE, 

Baltimore,  Md. 

1899. 


Oopyrighted,  1899 ;  all  rights  reserved. 


INDEX. 


Acetic  Add  Bacteria, 20,  8i 

.^robic,  26,  29,  43 

Agar  Peptone  Meat  Jelly,  .     ^ 50 

Alkaloid  Poisons, 10,  26,  29,  102 

Anaerobic, 20,  26,  29,  31,  43,  50,  64,  67,  78 

Anaerobic  Bacteria  Cultures, 50 

Anthrospore, J5 

Antiseptics,  8,  29,  69,  79,  97 

Apparatus  for  Study  of  Bacteria, 47 

Appert  of  Paris, 71 

Apples, 63 

Aspergillus  Glaucus, 17,  46,  96 

Babes, 28 

Bacillus  Amylobacter, 20,  23.  39,  41,  54,  78 

Butyricus,  20,  54,  78 

"       Comma  or  Cholera, 10,  27,  59,  102 

"       Cyanogenus, 57.  99 

"       Diphtheria  or  Klebs-Loeffler,        ....  9»  33i  59.  102 

"       Erythrosporus, 57 

"       Fluorescens  Putidus,  57.  83 

Lactici  Acidi,  19,  23,  37,  54,  81,  99 

"       Panificans,  25 

Prodigiosus, 23,  55,   58,  82 

Subtilis, 25,  42,  52,  57,  83 

"       Tetanus,  10,  31,  45,  6r,  102 

"       Typhoid, 10,  29,  60,  102 

"       Viscosus,  2T,  55,  83,  104 

Bacteria, 4,  5 

Bacteria,  Dead, 7,  9 

Bacterial  Multiplication, 37.  95 

Bacterium  Pasteurianum, 20 

Benzoic  Acid, 70 

Benzoate  of  Sodium, 70,  78 

Berries, 63 

Bitterness, 103 

Black  Rot  in  Tomatoes, 91 

Black  Spots  in  Corn,  91 

Black  Torulse,  91 

Boracic  Acid, 70 


83593 


INDEX. 


Boro-Glyceride, 

Bonilloti, 

Brefeld's  Pure  Culture  Method, 

Brieger, 

Brownian  Motion, 

Butyric  Ferments,     . 

Cadaverine, 

Calcium, 

Canning,  History  of 

Canning,  Scientific  Principles  of 

Can  Making  Methods,  Early 

Carbolic  Acid, 

Catsup,      .... 

Cells,   .... 

Cherries, 

Chili  Sauce, 

Chilling  Canned  Goods, 

Chloride  of  Zinc, 

Choline,    .... 

Chutney, 

Cleanliness, 

Cocci, 

Cohn's  Pure  Culture  Method, 

Conidia, 

Conidiaspore, 

Continuous  Heating, 

Corn,  .... 

Corn,  Dry  Pack, 

Corn,  Moist  Pack, 

Corn,  Sour, 

Corn,  Whiteness  of. 

Creosote, 

Culture,  Media, 

Deep  Wells, 

Delafontaine, 

Diplococci, 

Discontinuous  Heating  Process, 

Drying  As  a  Preservative, 

Duckwall,  Thomas, 

Dyes, 

Bhrenburg, 

Electricity,     . 

Endospore, 

Enzymes, 

Evaporation  As  a  Preservative, 

Eucalyptol,    . 

Fermentation, 

Fertilizing,     ... 

Fish,         .... 

Flagella,        .  .  .  . 

Fluid  Culture  Media,    . 


. 

70 

48 

. 

52 

10 

. 

. 

2 

i 

»  35 

,54 

• 

10 

.  26 
72 
71 
63 

• 

72 
70 
97 

15.  39> 

65, 

102 

• 

• 

63 
96 
90 
69 
10 

• 

• 

96 
66 

15 

52 

17 

79 

97 
17 
81 

19,  63, 

71 

81 

78 

84 

. 

78 

84 

80, 

82, 

88 

• 

78 

lOI 

47 
45 
II 

J5 

48, 

84 

104 

71 

16,  25, 

33, 

52 

23 

106 

15, 

23 

41 

103 

70 

9,  81,  y 

?5, 

103 

44 
100 

14, 

29 

47 

INDEX. 


Formic  Acid, 

. 

70 

Formic  Aldehj'de, 

. 

.      70 

Freezing,      .... 

.    27,  67,  88,  102 

Gelatine,             .            .            .            . 

20,  50 

Gelatinized  Meat  Peptone  Medium. 

Koch,   . 

50 

Germicides,        .            .            .            . 

.      31.  69,  97 

Halibut,        .... 

. 

.      lOI 

Hanging  Drop  Cultures, 

. 

•       51 

Hansen,        .    '        . 

. 

28 

Hay  Bacteria,     .            .            .            . 

. 

•    25,  42,  52,  57,  85 

Ice  Cream,    .         •  . 

. 

.     II,  102 

Inoculating  Media, 

. 

51 

Invertin,       .... 

. 

41 

Klebs, 

. 

•      52 

Klebs-Ivoeffler  Bacteria,     . 

. 

10,  33,  59.  102 

Koch, 

. 

27,  52 

Koch's  Pure  Culture  Method,      . 

. 

52 

Kraut,                  .            .            .            . 

.     103 

Kuhn's  Methylene  Blue, 

. 

51 

Lactic  Fermentation, 

•      19.  23,  37, 

42.  52,  63,  83,   lOI 

Leaks,           .... 

. 

80 

Leptrothrix,                   .        *   . 

.       15 

Light  EfiFect  on  Bacteria, 

. 

.    30.  105 

Lima  Beans,      .... 

63 

Lister's  Pure  Culture  Media, 

52 

Meats,                .... 

. 

loi,  102,  104 

Meat  Soups, 

96,  104 

Milk,- 

12,  19,  20,  27,  33, 

42,  48,  55,  63,  102 

Molasses, 

. 

21 

Mold, 

17,  39, 

46,  67,  79,  96,  103 

Monilia  Candida,  . 

19.  97 

Mucor  Racemosus, 

. 

19,  23,  96 

Muller,  Otto  Friederich, 

. 

5 

Muscarine,                                       .       ^ 

10 

Mycodernia  Aceti, 

20 

Mycoderma  Cerevisae, 

. 

16,  59,  78 

Mycoderma  Vini, 

. 

16,  69 

Mytilotoxiue, 

. 

II,  12 

Neurine,            .... 

. 

10 

Oysters,       .... 

.      63,  102 

Pasteur,            .... 

. 

6,  7,  20,  21,  28,  38 

Pathogenic  Bacteria, 

, 

26  to  36,  44,  102 

Peaches,           .... 

. 

62 

Pears,          .... 

63 

Peas,      ..... 

19,  62,  92 

Pencillium  Glaucum, 

• 

17,  46,  96 

Peptonization. 

. 

42 

Permanganate  of  Potassium,      . 

70 

Phenol,             .            .            . 

. 

•70 

Phenyl-Acetic  Acid, 

. 

70 

Phenylproprionic  Acid, 

. 

70 

VI 


INDEX. 


Pickles 

103 

Pigment  Forming  Bacteria, 

22,  52,   55,  82 

Pineapple,  ..... 

63 

Plums,   ...... 

....        63 

Pouchet,      ..... 

27 

Preserves, 

103 

Preserving  Processes, 

lOI 

Processing,       ..... 

62,  81,   84,  93 

Ptomaines,  .            . 

23,  27  to  45,  102 

Pure  Cultures,              .... 

47,  51,  82,  103 

Putrefaction,           .... 

.       •    .        19  to  3T,  43 

Putrescine,                    .... 

10,  27 

Registered  Temperature, 

84 

Resistant  Bacteria  to  Heat  and  Antiseptics, 

25,  42,  63  to  93 

Roberts  Pure  Culture  Methods, 

52 

Saccharomyces,           .... 

16,  36,   39,  95 

"                 Cerevisias, 

16,  59,  78 

"                 Apiculatus, 

23,  58 

Ellipsoideus,     . 

.       59,  78 

Salicylic  Acid,              .... 

.     70,  77,  91,  96,  99 

Salt, 

.    102,  103 

Smoked  Meats  and  Fish, 

•.    '        .            .            .102 

Soldering  Solutions, 

.      69,  103 

Solid  Culture  Media, 

.       50 

Soups,          ..... 

96,  99,  104 

Sour  Corn,          ..... 

.  78,  79.  88 

Sour  Tomatoes,     .... 

2,  95 

Spirilla, 

:        15 

Spontaneous  Generation, 

5 

Spores,  ...... 

.     14,  20,  25,  37,  83,  84,  88 

Spring  Bottoms  in  Canned  Goods, 

65 

Staining,            ..... 

14,  25,  33,  52 

Stanley's  Observations  in  Africa, 

32 

Steptococci,       ..... 

15 

Sturgeon,    ....'. 

lOI 

Sterilization,      ..... 

26,  48,  62,  81,  84,  93,  105 

Sugar,           ..... 

102 

Sulphurous  Dioxide,    .... 

70 

Surface  Water,        .... 

45 

Swells,     ...... 

78,  80 

Steam  Retorts,        .... 

72,  83,  90 

Temperatures,               .... 

27,  39,  62,  66,  81,  85 

Terebine,                 .            .            .            . 

70 

Tetanine,            ..... 

13,  31 

Tetanotoxine,         .... 

12 

Thymol,              ..... 

.70 

Tomatoes,    ..... 

•       63,  95 

Tomato  Catsup,             .... 

.       96 

Tomato  Pulp,           .... 

96 

Tomato  Soup,     ..... 

,     102 

Tyndall, 

.     6  to  7,  26.  85 

INDEX. 


Tyrotoxicon, 

Tyrotoxine, 

Vacuum, 

Van  Laer, 

Van  Leeuwenhoek,  Anthony, 

Vibrios,     . 

Vinegar, 

Villiers,     . 

Waste  Material, 

Winslow,  Isaac, 

Wood,  . 

X  Rays,      . 

^ooglae, 


13 

13 

64 

22 

5 

15 

21 

.    28 

67,  88 

•  71 

41 

30,  105 

15 


MICRO    PHOTOGRAPHS    AND    FIGURES- 


Figure     i.        Sour  Tomato  Juice, 

**  2.  Different  Forms  of  Bacteria, 

*'  3.  Saccharomyces,              .... 

"  4.  Saccharomyces,        .            .            .            .            . 

**  5.  Mycoderma  Yini  and  Cerevisiae, 

"  6.  Pencillium  Glaucus, 

"  7.  Monilia  Candida,           .... 

**  8.  Bacilli  Lactici  Acidi, 

'*  9.  Bacillus  Butyricus,         .... 

"  10.  Bacillus  Butyricus  Amylobacter,  . 

'*  II.  Mycoderma  Aceti.     Bacterium  Pasteurianum, 

**  12.  Bacillus  Viscosus,          .... 

'•  13.  Putrefactive  Bacteria  in  Bouillon, 

**  14.  Saccharomyces  Apiculatus.    Pineapple  Juice. 

'*  15.  Bacillus  Subtillus  on  Bouillon,     . 

'*  16.  Comma  Bacilli.               .... 

"  17.  Typhoid  Bacilli,       ..... 

"  18.  Tetanus  Bacilli,             .... 

"  19.  Klebs-Loeffler  Bacilli,         .... 

"  20.  Mold  Fungi  Submerged  in  Corn  Juice, 

"  21.  Bacteria  Found  in  Swelled  Can  of  Corn, 


Page 


2. 

14. 

15. 
16. 
16. 

17- 
18. 
19. 
20. 
21. 
21. 
22. 
23- 
24. 
25. 
27. 
29. 
31. 
33. 
79- 
80. 


22  and  23 

24.        Pencillium. 


Fermenting  Tomato  Juice  Showing  Degree 
of  Increase,        .  .  .  .    ' 


Aspergillus  Glaucus  Conidia 


96,  97- 
98. 


SUBJECTS. 


CHAPTER  I.  Page  i. 

Introduction— Cause  Leading  to  the  Study  of  Bacteriology — Sour  Toma- 
toes. 

CHAPTER  II.  Page  4- 

Bacteria  Defined— Forms — Multiplicity— Functions  Divided  Into  Two 
Classes— Discoveries— Spontaneous  Generation— Bacteria  in  the 
Atmosphere — Lister's '  Antiseptic  System  -Microscopical  Observa- 
tion—Chemistry  of  Fermentation  Ptomaines— What  Class  of  Bac- 
teria Produces  These  Poisons — Result  of  Ptomaine  Poisoning. 

CHAPTER  III.-  Page  13. 

Bacteria— Manner  of  Propagating — Description  of  Various  Forms — 
Characteristics — Mold  Fungi. 

CHAPTER  IV.  Page  19. 

Bacteria  Commonly  Found  in  Decomposing  Fruit  and  Vegetables— Micro- 
scopical Views  and  Descriptions— Characteristics— Sterilization. 

CHAPTER  V.  Page  26. 

Pathogenic  Bacteria— Studied  Because  of  the  Poisons  Produced  When 
Acting  on  Food  Products— Different  Kinds  of  These  Bacteria  Stud- 
ied—Their Action  on  Various  Food  Products  Described. 

CHAPTER  VI.  Page  36. 

Fermentation  -Object  of  Study  Is  to  Prevent— Alcoholic  Fermentation 
and  the  Germs  Which  Cause  It— Putrefaction— Disease  Fermenta- 
tion—Products of  Fermentation— Descriptive  Examples— Enzymes 
—Lactic  Fermentation -Benefits  to  Plants  and  Animal  Life— Fer- 
mentation Defined  in  a  Broad  Sense. 

CHAPTER  VII.  Page  47. 

Directions  For  Studying  Bacteria— Methods  to  Obtain  Pure  Cultures- 
Apparatus  to  Facilitate  the  Study— Inoculation  of  Solid  Culture 
Media— How  to  Cultivate  Anaerobic  Organisms— Hanging  Drop  Cul- 
tures—Staining. 


X  SUBJECTS. 

CHAPTER  VIII.  Page  53. 

A  Summary  of  the  Characteristics  of  Various  Organs  Found  in  Food 
Products— Bacillus  Lactici  Acidi— Bacillus  Butyricus— Bacillus 
Amylobacter— Bacillus  Prodigiosus— Bacillus  Viscosus— Bacillus 
Fluorescens  Putidus— Bacillus  Erythrosposus — Bacillus  Cyanoge- 
nus— Bacillus  Subtilis— Saccharomyces  Apiculatus— Saccharomyces 
Ellipsoideus— Saccharomyces  Cerevisae— Comma  Bacillus — Klebs- 
Lceffler  Bacillus— Typhoid  Bacillus— Tetanus  Bacillus. 

CHAPTEn  IX.  Page  62. 

Scientific  Principles  Involved  in  Canning  and  Preserving -Temperature- 
Vacuum — Anaerobic  Bacteria  and  Their  Action — Forms  Growing  in 
an  Anaerobic  State— Spring-Bottoms  in  Canned  Goods-  Causes — 
Precautions— Cleanliness— Disposal  of  Waste  Material— Soldering 
Solutions. 

CHAPTER  X.  ^        Page  69. 

Antiseptics  and  Germicides — Various  Chemicals  Used  As  Such. 

CHAPTER  XI.  Page  71- 

History  of  Canning — Discoverers— Appert,  of  Paris— Isaac  Winslow,  of 
Maine— Thomas  Duckwall  and  Albert  Fisher,  of  Ohio— Early  Can 
Making  and  Machinery — Steam  Retorts— Processors  and  Man- 
agers. 

CHAPTP:r  XII  Page  75. 

Two  Methods  of  Canning  Corn— Selection  of  Seed — Planting — Moist 
Process  — Dry  Pack— Whiteness— Swells— Sour  Corn— Differentia- 
tions Between  Swells  and  Sour  Corn— Cause  of  Sour  Corn— Steril- 
ization— Experiments  With  Various  Temperatures  For  Steriliza- 
tion—A Perfect  Process  — Discontinuous  Process — Processing — 
Black  Spots  in  Corn— Peas — Planting  Process — Tomatoes — Various 
Uses  of  Tomatoes  For  Making  Table  Condiments — Use  of  Anti- 
septics— Arguments  For  and  Against  Their  Use— Oysters— Meats 
— Fish— Preserving  Methods  —  Salting  —  Smoking— Sugar— Drying 
— Evaporating— Pickles— Sauer  Kraut— Soups. 

CHAPTER  XIII.  Page  104. 

Summing  Up— Bacteria  Studied— Products  Canned  and  Preserved— 
Sterilization  Studied— Mysteries  Cleared  Up— Recommendations — 
For  the  Study  of  Bacteriology— Electricity  the  Coming  Agent  For 
Sterilization— X-Rays— Finis. 


PREFACE. 


So  far  as  we  know  there  has  never  appeared  a  book  written  on  the 
subject  of  Bacteriology,  especially  as  it  applies  to  the  canning  and  pre- 
serving industries.  That  this  science  should  be  studied  and  applied  by 
all  persons  engaged  in  such  business  is  a  generally  conceded  truth,  and  it 
is  with  the  hope  that  a  great  deal  of  good  will  be  accomplished,  and  a 
great  many  of  the  mysteries,  that  have  caused  so  much  loss  to  our  pack- 
ers, may  be  cleared  up.  It  is  indeed  marvelous  how  nearly  hand  in  hand 
practical  work  and  science  travel,  for  looking  through  the  history  of  these 
industries  we  find  methods  discovered,  devices  employed  and  formulae 
adopted  and  used  as  the  results  of  innumerable  experiments,  and  where 
these  methods,  devices,  and  formulae  were  successful,  a  true  scientific 
principle  was  found  which  ought  to  have  been  seen  from  the  beginning, 
and  the  great  losses  in  experiments  and  experimenting  saved.  How  many 
men  who  fill  the  positions  of  superintendents,  managers,  processors  et  al., 
know  anything  at  all  about  the  scientific  part  of  their  work  ?  How  many 
men  engaged  in  these  enterprises  are  groping  along  in  the  dark  relying  on 
traditions  and  formulae  handed  down  as  a  positive  success,  and  who  never 
awaken  to  the  weakness  of  their  management  until  something  new  turns 
up,  until  some  new  menace  presents  itself  ?  Processors  have  their  rules 
by  which  to  work,  because,  for  some  unknown  reason  to  them,  the  goods 
will  spoil  if  treated  otherwise.  Do  you  know  that  years  ago  Tyndall  and 
Pasteur  gave  the  scientific  principle  to  the  world,  and  against  the  greatest 
opposition  proved  their  theories  ^nd  deductions  to  be  absolutely  cor- 
rect ?  After  all  the  experiments  made  in  this  business  we  find  that  these 
scientists  struck  the  key  note  and  unfolded  to  us  a  line  of  study  that  gives 
us  understanding.  It  is  with  the  hope  that  a  higher  knowledge  of  the 
canning  and  preserving  industries  may  be  obtained  here  that  this  little 
work  is  launched  among  the  productions  of  this  day. 

The  Author. 


OK    THK 

UNIVERSITY 


CHAPTER  I. 

INTRODUCTION.      CAUSE  LEADING  TO  THE  STUDY  OF  BACTERI- 
OLOGY.     SOUR   TOMATOES. 

In  the  fall  of  1891,  a  peculiar  trouble  came  to  my  notice,  with  a 
large  pack  of  tomatoes.  Many  cans  when  opened  appeared  to  be  in 
good  condition,  bright,  red  and  sound,  but  possessing  a  most  nau- 
seating, sour  taste.  Believing  that  this  was  due  to  a  careless  use  of 
the  soldering  solution,  chloride  of  zinc,  I  had  made  a  careful  analy- 
sis and  could  find  but  a  slight  trace  of  this.  I  was  then  puzzled  to 
know  just  what  caused  the  trouble  and  so  I  decided  to  make  some 
experiments.  The  analysis  showed  a  liberal  quantity  of  butyric  and 
lactic  acid,  also  a  trace  of  acetic  acid.  Fearing  that  we  had  been 
using  a  flux  which  was  not  pure,  an  analysis  proved  the  theory  to  be 
incorrect  and  it  then  dawned  upon  me  that  the  same  old  trouble 
that  I  had  many  times  seen  in  packing  corn,  had  in  some  unac- 
countable way  taken  possession  of  the  tomato  canning.  Cor- 
responding with  others  engaged  in  packing  tomatoes,  I  found  that 
several  had  experienced  trouble  of  this  nature  to  some  extent  but 
not  to  such  an  extent  as  to  cause  alarm  in  the  canning  of  to- 
matoes. I  knew  that  many  canners  had  experienced  heavy  losses 
in  canning  corn  and  some  fruits,  where  the  seeds  were  left  in  the 
can.  No  one  seemed  to  know  what  to  do  under  the  circumstances ; 
liberal  rewards  were  offered  to  anyone  who  could  save  the  corn, 
etc.,  by  some  of  the  canners  who  were  losing  so  much  goods,  and  I 
knew  of  several  who  were  severely  imposed  upon  by  unscrupulous 
persons,  who  claimed  to  know  how  to  prevent  the  complications. 

Up  to  this  time  I  had  never  given  a  thought  to  the  scientific 
principles  involved  in  canning  and  preserving.  Talking  over  the 
rules  with  experienced  processors,  I  found  that  they  were  carrying 
on  their  work  in  a  blind  way  and  following  rules  which  the  ex- 
pensive teacher,  Experience,  had  given  them  without  inquiring  into 
the  principles  of  scie^jce.  So  long  as  no  new  complications  pre- 
sented themselves  they  got  along  all  right,  but  when  the  conditions 
changed,  and  the  products  were  coming  in  too  fast,  and  the  changes 


2  BACTERIOLOGY  IN  CANNING. 

in  the  weather  were  unusual,  the  canners  suffered  losses  because 
they  were  following  iron-clad  rules  and  durst  not  launch  into  new 
channels  lest  their  losses  would  prove  overwhelming.  They  fol- 
lowed the  ''rule  of  thumb"  and  if  losses  came  they  were  put  down 
as  inevitable  and  they  called  them  a  part  of  the  expense  of  canning. 

Realizing  that  it  was  time  to  begin  a  scientific  study  of  the 
processes  of  canning  and  preserving  and  that  it  was  necessary  to 
know  how  to  meet  all  these  difficulties  which  were  constantly  aris- 
ing, and  so  follow  the  example  set  by  the  brewers  after  Pasteur  had 
revealed  the  nature  of  their  troubles  with  sour  beer,  I  decided  to  take 
up  the  study  of  bacteriology  and  apply  the  knowledge  to  this  busi- 
ness. Since  that  time  I  have  constantly  studied  this  science  and  the 
further  I  go  the  more  light  it  throws  upon  the  subject,  and  I  am  now 
prepared  to  say  that  every  man  who  is  engaged  in  these  enterprises 
should  immediately  begin  to  give  some  of  his  attention  to  the  sub- 
ject. By  arranging  a  little  room  and  procuring  a  few  instruments, 
the  subject  could  be  studied  during  the  dull  seasons  and  the  knowl- 
edge applied  during  the  canning  season  when  the  actual  process  of 
canning  begins. 

Another  incentive  for  taking  up  the  study  of  bacteriology  and 
applying  the  knowledge  to  this  industry,  was  my  hope  that  goods 
of  a  very  superior  quality  might  be  obtained,  simply  because  with 
a  certain  knowledge  of  just  how  to  treat  each  kind  of  goods  to  in- 
sure its  perfect  sterility,  and  therefore  its  keeping  qualities,  without 
doing  anything  in  excess  of  its  requirements,  to  wit,  if  under  certain 
conditions  a  temperature  of  250°  P".  for  seventeen  minutes,  would 
keep  tomatoes,  and  if  you  were  scientifically  correct,  you  would 
avoid  processing  the  same  goods  thirty  minutes.  By  this  you  would 
get  a  better  flavor  and  of  course  your  scientific  knowledge  should 
receive  the  credit.  As  I  stated  before,  I  decided  to  take  a  course 
of  study  in  this  science,  which  I  did.  I  took  up  a  number  of  experi- 
ments with  sour  tomatoes,  which  I  will  now  explain  because  they 
have  a  bearing  on  a  part  of  the  work  which  is  to  follow.  I  opened  a 
number  of  the  sour  cans  of  tomatoes,  and  after  filtering  some  of  the ' 
juice  through  a  cheese  cloth,  examined  it  under  the  power  of  a 
microscope  of  1000  diameters.  I  found  quite  a  number  of  small 
round  globules,  which  at  that  time  I  was  unable  to  understand. 
They  seemed  to  be  motionless  except  a  slight  quivering  which  is 
termed  Brownian  motion.  There  were  small  rods  and  little  fine 
dots  sometimes  alone,  sometimes  in  pairs,  and  looked  like  ants. 
There  were  also  small  forms  barely  perceptible  and  one  or  two 
'specimens  of  a  very  large  germ.  The  view  given  in  the  accompany- 


Figure  i 
MAGNIFIED  X   looo. 


BACTERIOLOGY  IN  CANNING.  3. 

ing  plate  is  just  as  it  was  taken.  I  left  this  juice  under  a  cover - 
glass  in  a  warm  room  for  two  days  and  it  remained  practically  un- 
changed, and  I  believed  that  the  germs  were  dead  and  so  they  were. 
To  determine  that  this  souring  of  tomatoes  was  caused  prior  to  the 
processing  was  my  only  solution,  because  the  germs  were  lifeless. 
I  took  a  number  of  cans  and  heated  them,  and  I  could  determine 
which  were  sour  because  they  would  be  slow  to  draw  in  again,  due 
to  the  presence  of  a  small  quantity  of  carbonic  acid  gas  which  had 
been  absorbed  by  the  tomato  and  which  the  heating  had  liberated. 
The  gas,  as  I  afterward  found  out,  was  that  which  had  been  capped 
in  the  can  while  the  tomatoes  were  fermenting  before  processing. 
Taking  a  number  of  swelled  cans  of  tomatoes  in  various  degrees 
of  fermentation,  I  cut  them  open  and  filled  new  cans  with  the  con- 
tents and  immediately  gave  them  thirty  minutes  boiling,  at  212^  F. 
I  had  four  cans.  A,  B,  C  and  D.  A  was  taken  from  a  can  very  badly 
swelled  and  hot  with  fermentation.  D  was  taken  from  a  can  which 
had  just  started  to  ferment,  and  B  and  C  were  taken  from  cans 
which  were  bulged  out  just  a  little  more  than  D.  After  processing 
these  cans  in  water  for  thirty  minutes,  I  took  them  out,  chilled  them 
and  set  them  to  one  side  to  await  results.  D  drew  in  first  and  it  was 
several  days  before  A  finally  looked  all  right,  but  it  was  quite  short 
in  weight  and  not  nearly  full.  I  decided  to  open  these  cans  and  de- 
termine if  I  had  anything  similar  to  my  sour  tomatoes,  and  you  may 
imagine  my  surprise  to  find  them  almost  exactly  the  same;  espe- 
cially was  this  true  of  B,  C  and  D,  while  A  represented  an  unusual 
example,  being  too  violent.  It  was  evident  then  that  our  sour  toma- 
toes were  sour  before  the  processing  and  that  the  heat  had  killed 
the  organisms,  but  the  unpleasant  results  of  the  fermentation  were 
absorbed  by  the  tomatoes  in  the  can  together  with  whatever  car- 
bonic acid  gas  was  present  in  the  fermenting  tomatoes.  The  ques- 
tion then  arose,  where  and  when  was  this  fermentation  started  and 
what  were  the  causes.  We  found  that  about  twenty  per  cent,  of  the 
entire  pack  had  suffered  during  the  month  of  September  when  the 
weather  had  been  quite  warm,  and  warm  rains  had  been  frequent. 
The  farmers  had  brought  in  the  product  very  fast  and  we  were 
bothered  with  a  gray  mold  whenever  the  tomatoes  stood  in  the 
boxes  for  a  few  hours. 

The  peculiar  manner  of  our  canning  had  been  to  heat  the  filled 
cans  in  steam  boxes  and  then  take  them  to  the  capping  machines. 
It  frequently  happened  that  "these  would  accumulate  ahead  of  the 
automatic  capping  machines,  particularly  when  something  would  get 
out  of  order  about  them,  when  they  would  sometimes  stand  for  a 


4  BACTERIOLOGY  IN  CANNING. 

half  hour  in  a  temperature  of  90°  to  100^  F.  Here  then  was  where 
the  fermentation  started  and  this  was  the  secret  of  the  whole 
trouble.  A  scientific  knowledge  would  have  obviated  this  difficulty 
at  once  and  saved  a  severe  loss.  During  the  next  season  I  verified 
this  theory  by  making  actual  experiments  in  this  line,  by  taking  a 
number  of  cans  and  allowing  them  to  stand  in  a  warm  place  for  a 
considerable  time  and  also  taking  some  which  did  not  stand.  The 
former  were  without  exception  sour  and  unfit  for  food  after  the  pro- 
cess, while  the  latter  were  perfectly  good  in  every  respect. 

CHAPTER  II. 

BACTERIA      DEFINED.        FORMS.         MULTIPLICITY.         FUNCTIONS. 

DIVIDED     INTO     TWO    CLASSES.      DISCOVEKIES.      SPONTANEOUS 

GENERATION.     BACTERIA  IN  THE  ATMOSPHERE     LISTER'S 

ANTISEPTIC  SYSTEM.      MICROSCOPICAL  OBSERVATIONS. 

CHEMISTRY  OF  FERMENTATION  PTOMAINES.    WHAT 

CLASS     OF     BACTERIA     PRODUCES     THESE 

POISONS.    RESULT    OF    PTOMAINE 

POISONING. 

We  will  now  take  up  the  study  of  bacteria,  particularly  the 
varieties  peculiar  to  the  destruction  of  the  various  products  which 
are  canned  in  hermetically  sealed  packages.  We  will  study  their  hfe^ 
history,  their  mode  of  propagation  and  the  conditions  most  favor- 
able for  their  development.  We  will  also  go  into  the  subject  to  de- 
termine safe  methods  to  guard  against  their  action. 

Bacteria  are  the  lowest  form  of  living  things.  They  are  organ- 
isms of  various  forms  and  shapes,  round,  rods,  ellipsoid,  thread, 
spiral,  dumb-bell,  spindle,  etc.  Each  is  a  small  speck  of  protoplasm 
called  a  cell  and  exceedingly  small.  Micrococci  measure  about 
i^Thss  part  of  an  inch  in  diameter.  They  multiply  with  marvelous 
rapidity  and  if  suitable  conditions  were  all  right  one  germ  of  many 
varieties  could  produce  or  multiply  to  the  extent  of  5000  billions  in 
three  days.  Such  conditions  however  do  not  ordinarily  exist  and 
many  of  them  die  of¥  because  of  peculiar  changes  produced  by  their 
own  action  on  the  medium,  upon  which  they  are  thriving.  The  use- 
fulness of  many  of  these  bacteria  in  destroying  accumulated  vege- 
table and  animal  matter  is  very  great.  If  it  were  not  for  these 
minute  organisms  all  this  matter  would  accumulate  and  would  not 
be  reduced  to  elementary  forms  so  necessary  for  new  plant  and  ani- 
mal life.  All  things  that  die  would  remain  and  the  animal  and  vege- 
table kingdoms  would  soon  become  extinct.  A  dead  animal  or  dead 


BACTERIOLOGY  IN  CANNING.  5 

vegetation  under  the  action  of  these  germs  is  with  wonderful 
rapidity  reduced  to  the  elementary  forms  to  nourish  new  vegetable 
and  animal  Hfe. 

We  may  divide  for  our  consideration  bacterial  life  into  two 
distinct  classes,  viz :  those  which  merely  act  as  ferments  and  are  not 
disease  producing  in  man,  and  those  which  produce  disease.  With 
the  former  we  have  largely  to  deal  because  it  is  by  their  action  that 
the  complications  arise  in  the  preservation  of  food  products.  But  we 
have  also  something  to  say  of  the  latter  because  of  the  results  of 
their  action  at  times  on  food  products,  causing  ptomaines  which  are 
alkaloids,  and  deadly  poison  to  man,  and  which  have  been  the  cause 
of  so  much  discussion  among  medical  men  in  the  late  years,  from 
the  fact  that  people  have  at  times  died  from  eating  certain  kinds  of 
fish  and  meat.  Cheese  and  ice  cream  have  been  known  to  cause  the 
death  of  persons  under  most  seemingly  unaccountable  circum- 
stances. 

As  a  rule  bacteria  are  colorless  and  refractile  in  a  clear  liquid 
but  may  be  colored  and  identified  by  their  affinity  for  certain  kinds 
of  dyes  which  give  them  a  clear  outline  and  makes  them  easy  to 
study  under  a  suitable  instrument.  The  first  man  to  discover  that 
there  was  such  a  thing  as  bacteria  was  Anthony  van  Leeuwenhoek,a 
native  of  Delft,  Holland,  who  in  1675,  with  only  a  crude  instrument 
of  his  own  design,  discovered  minute  organisms  with  motility  in  de- 
cayed matter.  He  says :  *'I  saw  with  very  great  astonishment  that 
there  were  many  small  animals  which  moved  about  in  a  most  arnus- 
ing  manner,  the  largest  of  these  showed  the  liveliest  and  most  active 
motion,  moving  through  rain  water  or  saliva  like  a  fish  of  prey  darts 
through  the  water ;  this  form,  though  few  in  numbers,  was  met  with 
everywhere.  A  second  form  moved  round  often  in  a  circle;  these 
were  present  in  greater  numbers.  They  were  tiny,  in  addition  they 
moved  forward  so  rapidly  that  they  tore  through  one  another  like 
a  swarm  of  midges  and  flies  buzzing  in  and  out  between  one 
another.  I  had  the  impression  that  I  saw  several  thousand  in  a 
single  drop  of  water  or  saliva  which  was  mixed  with  the  matter 
under  observation  not  larger  than  a  grain  of  sand.  Some  were 
curved,  some  straight,  lying  irregularly  and  interlaced."  These  re- 
markable statements  made  at  so  early  a  date,  give  us  the  first  his- 
tory of  the  rod  shaped  bacteria  bacilla,  spirilla  and  round  shaped 
micrococci.  These  statements  caused  a  great  deal  of  excitement  and 
research  by  scientists,  and  many  peculiar  theories  were  advanced. 
Otto  Friederich  Muller,  of  Copenhagen,  was  the  first  man  who  un- 
dertook to  classify  the  different  kinds  of  bacteria,  and  he  certainly 


6  BACTERIOLOGY  IN  CANNING. 

made  remarkable  progress,  considering  the  very  crude  microscopes 
made  in  his  time.  Other  scientists  took  up  the  work  and  the  oppo- 
sition took  the  ground  that  these  scientists  were  not  deaHng  with 
germs,  but  merely  albuminoid  matter  found  in  the  air.  The  matter 
was  not  cleared  up  until  the  time  of  Tyndall  and  Pasteur,  who 
brought  the  science  out  of  its  chaotic  state  and  proved  their  work 
step  by  step,  and  it  is  due  to  the  two  men  who  overthrew  the  theory 
of  spontaneous  generation  that  this  science  is  to-day  on  such  a  sure 
footing. 

For  many  years  the  theory  that  these  organisms  were  a  spon- 
taneous production  of  decaying  matter,  was  generally  accepted  as 
truth.  When  meat  was  exposed  in  hot  weather,  it  soon  filled  with 
worms,  and  it  was  thought  that  they  generated  of  themselves,  until 
someone  covered  it  with  wire  gauze  and  the  flies  deposited  their 
eggs  on  the  wire  and  proved  the  fallacy  of  the  theory.  The  belief 
in  spontaneous  generation  was  entertained  by  many  scientists  prior 
to  and  contemporaneous  with  Pasteur,  among  whom  most  notably 
were  Schultz  and  Von  Liebig.  They  took  infusions  of  mutton  broth ' 
and  different  vegetables,  and  having  sterilized  them  perfectly  by 
heat  so  that  no  micro-organisms  were  visible  under  the  microscope, 
they  allow  them  to  stand  open  and  exposed  to  the  atmosphere  for 
several  days,  examining  them  constantly.  Suddenly  putrefactive 
organisms  and  ferments  peculiar  to  the  infusion,  would  make  their 
appearance  most  unaccountably  to  them,  so  they  advanced  the 
theory  that  life  was  spontaneous,  and  even  built  up  a  framework 
for  the  existence  of  all  living  things  on  this  theory.  Tyndall  and 
Pasteur  were  not  believers  in  this  theory,  and  took  up  a  series  of  ex- 
periments to  demonstrate  that  the  germs  were  deposited  from  the 
air  or  atmosphere.  They  had  very  great  difficulties  to  contend  with, 
because  it  was  generally  thought  that  these  low  forms  of  life  were 
easily  destroyed  by  boiling  at  a  temperature  of  212^  F.  It  was  found 
however,  that  many  of  their  infusions  would  break  down,  become 
turbid,  evolve  carbonic  acid  gas,  after  having  been  subjected  to 
the  boiling  temperature  for  several  hours.  The  opposition  strength- 
ened themselves  in  their  theory  because  they,  too,  had  tried  these 
experiments,  and  the  result  was  that  in  nearly  all  cases  they  were 
unsuccessful  in  preserving  their  infusions,  especially  those  made 
from  meats  and  some  vegetables,  which  had  bacteria  of  more  resist- 
ant power  than  others.  After  making  various  experiments  in  test 
tubes  where  the  glass  was  drawn  to  a  fine  point  at  the  top  to  allow 
the  steam  to  escape  during  the  heating,  and  while  still  boiling  they 
closed  the  escape  by  melting  the  glass  together,  they  were  enabled  to 


BACTERIOLOGY  IN  CANNING.  7 

obtain  many  perfectly  sterile  infusions,  which  kept  for  a  number  of 
years  perfectly  clear  and  transparent.  They  adopted  various  tem- 
peratures, both  continuous  and  discontinuous,  and  were  able 
to  sterilize  any  kind  of  fluid.  Their  failures  in  many  cases  were  due 
to  their  test  tubes  not  being  full  of  liquid  so  that  the  air  space  be- 
tween the  boiling  liquid  and  the  point  of  exit  would  contain  the  dry 
spores  of  bacteria  which  would  afterward  develop  when  the  liquid 
cooled  off. 

Having  accomplished  the  overthrow  of  the  theory  of  sponta- 
neous generation,  Tyndall  even  went  further  and  demonstrated  by 
the  question  of  a  doubt  that  the  atmosphere  furnished  these  low 
forms  of  life.  He  made  a  pure  air  chamber  and  covered  all  over 
on  the  inside  with  glycerine;  this  chamber  had  windows  through 
which  he  passed  an  electric  beam.  So  long  as  there  was  any  float- 
ing matter  within  the  chamber,  the  light  would  be  refracted  just 
as  a  ray  of  light  passing  through  a  dark  room  is  refracted  by  the 
particles  of  dust,  which  we  have  all  seen.  When  the  light  ceased  to 
be  refracted  and  the  beam  passed  entirely  through  the  chamber 
without  lighting  it,  it  was  evident  that  the  particles  had  settled  and 
stuck  fast  to  the  glycerine.  In  this  chamber  then  he  placed  many 
different  kinds  of  sterilized  infusions  and  they  kept  without  show- 
ing any  signs  of  breaking  down  or  fermenting.  It  is  to  these  two 
geniuses,  Pasteur  and  Tyndall,  that  we  owe  all  that  we  know  of  the 
method  of  sterilizing,  and  their  deductions  come  to  us  who  are  in 
the  canning  and  preserving  industries,  as  a  solution  of  all  our 
troubles.  Bacteria,  then  as  we  learn,  are  present  everywhere  in  the 
free  atmosphere,  and  we  find  them  present  in  quantities  or  numbers 
in  proportion  to  the  amount  of  organic  matter  which  is  undergoing 
decomposition.  They  are  present  in  the  air,  clinging  to  dust  or  any 
floating  matter  and  if  no  suitable  medium  is  found  by  them  to  en- 
able them  to  vegetate  they  become  hard  and  dry,  and  in  the  course 
of  time  will  die.  Pasteur,  however,  demonstrated  that  many  varie- 
ties would  live  for  two  years.  When  we  consider  the  vast  amount 
of  organic  matter  which  is  undergoing  decomposition  every  year, 
the  grass,  the  leaves,  all  vegetation  and  animal  life,  it  is  no  wonder 
then  that  the  atmosphere  is  everywhere  laden  with  countless  num- 
bers. Many  of  the  different  varieties  are  useful  directly  to  man; 
the  butyric  ferment  for  instance  is  so  useful  in  ripening  cheese  and 
making  butter,  that  this  form  is  cultivated  and  employed  in  some  of 
the  best  creameries,  just  as  the  brewers  cultivate  and  sow  their 
yeast.  Just  how  or  when  these  low  forms  of  life  first  made  their  ap- 
pearance, we  do  not  know,  but  it  is  likelv  that  thev  have  existed 


8  BACTERIOLOGY  IN  CANNING. 

since  creation,  and  their  origin  like  that  of  every  living  thing,  is 
shrouded  in  mystery.  It  is  a  surprise  that  the  existence  of  this 
world  of  living  things  should  have  remained  unknown  to  man 
through  so  many  centuries.  When  we  think  of  the  incalculable  value 
of  such  knowledge,  we  wonder  how  man  could  get  along  without 
knowing  of  their  existence.  The  dreaded  diseases  came  on  man  and 
he  called  them  the  plague,  sent  by  God  upon  man.  We  are  thinking 
of  the  terrible  plague,  the  Black  Death,  which  made  its  appearance 
and  nearly  depopulated  the  world  at  one  time.  The  superstitious 
people  crowded  together,  offered  prayers  and  made  offerings,  used 
charms  and  did  everythin'g  imaginable  to  stop  the  progress  of  the 
disease.  They  did  not  know  that  it  was  caused  by  these  low  forms  of 
life,  for  if  they  had  known  it,  they  could  have  taken  sanitary  meas- 
ures to  stop  it.  In  the  late  Civil  War,  limbs  were  amputated  with- 
out the  use  of  the  carbolic  acid  spray,  and  men  died  of  gangrene  and 
blood  poisoning.  Lister  was  the  discoverer  of  the  antiseptic  spray  to 
keep  the  germs  in  the  air  from  acting  on  the  tissues,  when  surgical 
operations  were  performejd,  and  we  can  now  see  where  many  brave 
and  valiant  soldiers  perished  from  blood  poisoning  where  this  car- 
bolic spray  would  have  saved  their  lives. 

Owing  to  the  minuteness  of  these  organisms  the  study  of  their 
life  and  nature  becomes  a  science,  and  is  a  field  for  advanced  re- 
search. It  is  not  like  taking  up  the  study  of  things  we  can  see  with 
the  naked  eye,  and  watch  from  day  to  day  their  habits  and  purposes 
and  results,  but  it  is  a  study  when  only  a  small  field  of  observation 
can  be  watched  for  a  limited  time  and  the  results  can  only  be 
studied  as  we  watch  their  action  through  a  powerful  microscope. 
With  the  best  instruments  obtainable  in  this  advanced  age,  we  find 
ourselves  limited  for  the  want  of  sufficient  light,  for  the  greater  the 
magnifying  power  of  the  glass,  the  greater  amount  of  light  is  re- 
quired, and  it  must  be  a  peculiar  light  too,  not  glaring  as  the  direct 
rays  of  the  sun,  but  the  soft  rays  of  light  reflected  as  from  white 
clouds  or  the  electric  light.  Owing  to  the  transparency  of  most  of 
these  organisms  it  is  necessary,  especially  for  the  examination  of 
the  smaller  forms,  to  use  certain  kinds  of  dyes,  otherwise  you  might 
exanxine  a  field  and  very  few  forms  would  be  visible.  It  is  very  in- 
teresting to  watch  the  working  of  bacteria  on  the  particular  sub- 
stratum that  you  wish  to  examine.  For  instance,  if  you  desire  to  ex- 
amine fermenting  corn  you  would  take  some  of  the  juice  and  put  a 
small  quantity  under  a  cover  glass,  which  is  a  very  thin  piece  of 
glass  about  ^^-g-  of  an  inch  in  thickness,  and  when  you  brought 
the  field  to  a  proper  focus  you  would  find  a  very  turbid  view  and 


BACTERIOLOGY  IN  CANNING.  9 

you  would  be  unable  to  gain  much  of  an  idea  of  the  germs  you 
wished  to  examine.  You  could  filter  a  small  quantity  of  sweet  juice 
and  then  by  dipping  a  needle  in  the  fermenting  juice,  transfer  some 
of  the  germs  to  this  and  then  transfer  a  small  quantity  to  the  plate, 
and  place  the  cover  glass  over  this  to  diminish  evaporation,  then 
you  could  watch  the  active  bacteria  begin  their  work  of  decompo- 
sition. In  coloring  the  bacteria,  a  small  quantity  of  methyl  blue  or 
eosine  will  often  bring  them  clearly  to  view.  It  is  in  the  results  of 
bacterial  action  that  we  are  most  interested,  as  they  bring  about 
chemical  action  and  change  the  atoms  from  one  group  of  molecules 
to  another  and  form  new  compounds  and  create  gases.  If,  for  in- 
stance, we  take  sugar  and  allow  the  yeast  plant  to  work  on  a  pre- 
pared solution,  we  find  that  it  is  broken  up  into  different  forms. 
We  will  represent  one  molecule  of  sugar  by  its  atomical  symbols 
which  is  CeHiiOe  which  is  six  atoms  each  of  carbon  and  oxygen 
and  twelve  atoms  of  hydrogen.  By  the  action  of  the  yeast  plant, 
which  is  called  saccharomyces  we  get  2CO2  (carbonic  acid)  -f  2C2 
HeO  (alcohol)  which  are  two  distinct  substances  and  not  resembling 
at  all.  Now  if  the  putrefactive  ferment  butyricus  amylobacter  acts 
on  the  alcohol  we  will  have  2C2H6O  (alcobol)=C4H802  (butyric 
acid)+  2H2  (hydrogen)  or  if  we  let  the  lactic  ferment  act  directly 
on  the  sugar  in  conjunction  with  the  butyric  ferment,  we  will  have 
the  sugar  converted  directly  into  lactic  acid  which  in  its  turn  is 
converted  into  butyric  acid,  carbonic  acid  and  hydrogen.  CeHia 
Oe  (sugar)  =  2C3H6O3  (lactic  acid)  =  C4H8O2  (butyric  acid  -f  2H2 
{hydrogen). 

Thus  we  see  our  molecule  of  sugar  broken  up  first  into  two 
molecules  of  lactic  acid  which  in  its  turn  is  broken  up  into  two  fatty 
acids,  and  two  molecules  of  hydrogen,  or  in  other  words  one  mole- 
cule of  sugar  broken  up  into  five  molecules,  which  is  the  tearing 
down  process  of  these  organisms  to  reduce  or  decompose  sub- 
stances into  elementary  forms.  I  do  not  mean  to  say  that  the  pro- 
cess ends  where  I  have  brought  it,  for  there  are  still  lower  forms  of 
bacteria  which  take  up  the  work  and  reduce  these  molecules  still 
further  until  they  take  simple  forms,  even  elementary  forms.  I 
think  the  above  chemical  formulae  should  be  very  interesting  and 
instructive,  as  they  give  you  the  idea  of  bacterial  action  better  than 
any  description  in  words. 

We  have  been  describing  the  action  of  certain  bacteria  which 
act  only  on  dead  matter  which  are  not  classed  properly  with  the 
disease  germs.  To  be  sure  if  we  take  into  our  stomachs  fermenting 
substances  we  are  liable  to  suffer  with  some  disorder,  and  perhaps 


10  BACTERIOLOGY  IN  CANNING. 

severe  sickness,  but  the  difference  between  this  action  and  the  action 
caused  by  disease  germs  properly  speaking  is  very  great.  We  will 
enter  into  a  description  of  the  various  diseases  produced  by  this 
class  of  bacteria  further  than  to  observe  their  action  on  certain  foods 
which  when  taken  into  the  stomach  produce  certain  kinds  of  poison- 
ing, resembling  arsenic  and  strychnine.  Brieger  obtained  from  pure 
cultures  of  the  typhoid  bacillus  acting  on  some  suitable  medium,  a 
ptomaine  which  termed  typhotoxin,  and  from  the  tetanus  bacillus 
he  obtained  tetanotoxin.  The  vegetable  kingdom  furnishes  many 
substances  that  have  an  alkaline  reaction,  combine  with  the  acids 
and  form  salts,  which  if  injected  into  animals  or  taken  into  the 
stomach  cause  poisoning,  viz:  nicotine,  morphine,  brucine,  strych- 
nine and  hydrocyanic  acid.  So  these  bacteria  of  disease  or  patho- 
genic organisms,  which  are  of  vegetable  nature,  can  produce 
poisons  in  food  products  where  they  may  happen  to  find  a  substra- 
tum favorable  to  their  growth.  In  plainer  language  then,  since  the 
higher  order  of  plant  life  can  furnish  these  dreadful  poisons,  so  the 
lower  vegetable  forms  produce  poisons  just  as  deadly  and  of  nearly 
the  same  reaction  as  the  higher  forms.  Nearly  all  the  known  patho- 
genic organism  produce  poisons  which  would  properly  be  termed 
ptomaines.  Putrescine  (C4H12N2),  cadaverine  (C5H16N2)  are 
ptomaines,  the  latter  is  produced  by  an  action  of  the  cholera  bacil- 
us  on  egg  albumen.  Neurine  (C5Hi2(NO) ),  and  choline  CsHisN 
O2,  are  also  produced  in  putrefying  flesh  by  the  agency  of  patho- 
genic bacteria.  We  find  also  another  poison  growing  naturally  in 
a  kind  of  poisonous  mushroom  and  also  produced  in  putreying  fish 
by  bacteria.  This  ptomaine  is  muscarine  (C5H15NO2),  and  acts  on 
the  muscles  when  eaten.  Oysters  and  mussels  are  very  liable  to 
the  action  of  certain  bacteria  which  produce  mytilotoxine,  CeHisN 
O2).  Tyrotoxine  (C7H17NO2)  is  found  in  cheese  and  ice  cream, 
where  these  foods  have  undergone  a  fermenting  process  by  the 
agency  of  disease  germs.  The  diphtheria  germ,  Klebs-Loeffler 
bacillus  produces  a  toxic  poison,  so  also  do  the  bacilli  of  cholera, 
typhoid,  tetanus  others. 

Studying  over  these  deductions  and  chemical  changes,  we  see 
that  combinations  are  easily  upset,  atoms  from  one  set  of  molecules 
fall  dow^n  and  are  taken  up  by  other  molecules,  forming  new  sub- 
stances by  these  mere  changes  in  arrangement.  If  we  cannot  see 
the  exact  changes  chemically  made,  we  can  see  the  agents  at  work 
and  we  can  see  how  they  perform  the  work. 

The  word  ptomaine  comes  from  the  Greek  word  Trrw/ia,  which 
means  "cadaver"  and  was  bestowed  upon  them  by  Selmi,  an  Italian 


BACTERIOLOGY  IN  CANNING.  ii 

chemist.  Delafontaine  gives  a  very  interesting  explanation  of  these 
poisons :  ''During  the  incipient  state  of  putrefaction  there  are  fre- 
quently produced  various  compounds,  some  of  which  possess  in- 
tensely poisonous  properties.  They  are  called  ptomaines.  They  seem 
to  have  led  some  experts  into  trouble,  for  the  reason  that  some  of 
them  produce  symptoms  similar  to  those  of  various  natural  poisons 
such  as  strychnine,  morphine,  nicotine,  etc.  Such  poisons  have  been 
extracted  from  cheese,  milk,  especially  in  the  form  of  ice  creams, 
and  various  preparations  of  meats,  such  as  sausage,  smoked  meat 
and  fish. 

''The  action  of  some  of  these  upon  the  healthy  man  very  much 
resembles  that  of  arsenic  and  other  like  irritating  poisons.  Almost 
every  summer,  one  chemist  or  another  has  to  investigate  cases  of 
poisoning  from  ice  cream,  especially  resulting^iFom  parties  or  pic- 
nics, where  a  number  of  people  are  made  more  or  less  sick  from  the 
effects  of  eating  the  compound.  The  first  impulse  of  victims  and 
friends  is  to  ascribe  the  trouble  to  the  presence  of  copper,  lead  or 
zinc  absorbed  by  the  cream  from  the  freezers.  Sometimes  the  blame 
is  laid  at  the  door  of  the  flavoring  extract  employed,  especially  if  it 
chances  to  be  vanilla.  But  almost  invariably  the  closest  chemical 
analysis  fails  to  sustain  the  suspicions  and  leads  to  the  extraction 
of  a  ptomaine  identical  with  or  closely  allied  to  that  sometimes 
found  in  cheese.  Incidentally  it  may  be  stated  that  on  the  whole^ 
the  poison-tainted  articles  exhibit  no  bad  taste  or  smell,  that  would 
act  as  a  warning  to  the  consumer. 

"As  regards  some  of  the  symptoms  frequently  exhibited,  they 
are  like  those  of  a  very  irritating  poison.  Among  other  cases,  I 
once  was  called  to  examine  some  meat  eaten  by  fifteen  persons  who 
were  poisoned.  They  developed  acute  inflammation  of  the  stomach 
and  bowels,  repeated  vomiting  and  purging,  wdth  great  loss  of 
strength,  clammy  perspiration  and  cold  extremities.  There  was 
nothing  in  the  appearance,  taste  or  smell  of  the  meat  to  indicate 
that  it  was  unsound,  and  yet  I  could  extract  from  some  parts  of  it 
a  poison  which  wa's  undoubtedly  a  ptomaine. 

"Poisoning  by  ptomaines  is  by  no  means  uncommon,  yet  many 
suspected  cases  are  due  only  to  over  indulgence  in  strongly  spiced 
articles  and  too  much  drinking  of  beer,"  etc. 

There  is  an  interesting  article  also  in  the  Scientific  American, 
which  gives  some  useful  information  on  the  subject  of  ptomaines. 
It  says:  "Within  the  last  few  days  a  number  of  persons  in  New 
York  City  have  died  from  ptomaine  poisoning,  so  that  public  at- 
tention is  now   directed    toward    the    mysterious    nature    of   these 


12  BACTERIOLOGY  IN  CANNING. 

poisons,  which  are  not  generally  well  understood.  'Ptomaine'  is  a 
generic  name  for  alkaloid  bodies  formed  from  animal  and  vegetable 
tissues  during  putrefaction  and  the  similar  bodies  produced  by 
pathogenic  bacteria.  Very  often,  perhaps  generally,  the  degenera- 
tion in  the  food  product  is  not  far  enough  advanced  to  offend  either 
the  taste  or  sense  of  smell ;  consequently,  suspicion  is  not  excited, 
and  a  person  eats  or  drinks  something  which  contains  enough  of 
the  poison  to  make  a  great  deal  of  trouble,  if  the  result  is  not  fatal. 
We  often  hear,  in  the  summer,  for  instance,  that  persons  who  at- 
tend a  picnic  were  stricken  with  a  violent  illness,  and  that  the  phy- 
sicians in  the  neighborhood  were  kept  busy  for  hours.  The  fact  is 
developed  that  only  those  who  ate  ice  cream  were  made  sick.  Some- 
times it  is  reported  that  some  one  has  poisoned  the  food  maliciously, 
but  it  is  known  that  the  cause  of  most,  if  not  all,  of  these  distressing 
experiences  was  the  presence  of  ptomaines  in  the  milk  out  of  which 
the  ice  cream  was  made. 

''It  is  not  an  easy  task  to  trace  the  history  of  milk  back  far 
enough  to  reveal  the  precise  conditions  under  which  the  ptomaines 
were  developed,  but  it  is  believed  that  failure  to  properly  cool  the 
milk  immediately  after  it  was  taken  from  the  cows,  is  a  partial  ex- 
planation of  the  evil.  Warm  weather  favors  this  condition.  The 
ptomaines  of  ice  cream  tyrotoxicon  are  particularly  to  be  dreaded, 
as  well  as  other  poisons,  such  as  mytilotoxin,  found  in  mussels. 

"It  is  not  pleasant  to  contemplate  that  the  air  we  breathe  and 
the  water  we  drink,  and  a  large  proportion  of  our  food  abounds  in 
bacteria  of  different  kinds.  Most  of  them  are,  fortunately,  harm- 
less, or  should  be,  if  proper  precautions  are  taken.  Milk  is  far  from 
being  the  only  medium  for  the  transference  of  this  poison  to  human 
beings.  A  great  variety  of  solid  foods  of  animal  origin  are  also 
likely  to  develop  ptomaines.  One  frequently  hears  of  poisoning  by 
canned  goods,  such  as  potted  meats  or  canned  salmon,  for  instance. 
In  some  cases  a  metallic  agent,  perhaps  the  solder,  is  the  cause  of 
the  trouble,  but  in  the  majority  of  cases  the  sickness,  especially  if 
it  is  intestinal  and  painful  character,  is  due  to  ptomaines.  To  all  ap- 
pearances, the  food  may  be  entirely  fit  for  consumption,  and  per- 
haps none  of  those  employed  in  the  canning  house  may  be  re- 
sponsible, but  the  chances  are  that  unperceived  putrefaction  has  set 
in  and  that  ptomaines  have  been  produced. 

''Fresh  fish  and  oysters  are  not  exempt  from  the  tendency  to 
develop  ptomaines.  Indeed,  fish  was  one  of  the  first  sources  from 
which  these  poisons  were  obtained  by  chemists.  The  symptoms  of 
these  poisons  are  vomiting,  nausea,  diarrhoea  and  retarded  respira- 


BACTERIOLOGY  IN  CANNING. 

tion,  and  in  advanced  stages,  coma. 

'There  is  no  known  antidote  for.  this  poison,  though  of  course 
emetics  and  purgatives  should  be  used  where  the  poison  is  sus- 
pected. There  are  numerous  ptomaines  in  the  body,  but  they  are 
absorbed  by  the  oxygen  or  expelled  by  the  bowels,  liver  and  lungs. 
If  not,  they  strike  the  nerve  centers  and  sickness  results.  The  real 
cause  of  many  mysterious  deaths  is  ptomaine  poisoning,  but  there 
are,  of  course,  many  mysterious  deaths  due  to  other  causes.  Many 
cases  of  ptomaine  poisoning  do  not  result  seriously  at  all." 

CHAPTER  III. 

BACTERIA.      MANNER    OF    PROPOGATING.      DESCRIPTION  OF  VARI- 
OUS   FORMS.      CHARACTERISTICS.      MOLD   FUNGI. 

The  multiplication  of  bacterial  forms  vary  in  different  organ- 
isms, and  it  may  be  well  to  take  up  the  study  of  these  different  forms 
before  engaging  our  attention  on  the  various  organisms  peculiar  to 
the  decomposition  of  food  products. 

Multiplication  by  division  is  a  common  mode,  especially  with 
the  spirillum  and  bacillum.  Transverse  lines  become  visible,  which 
increase  and  become  gelatinous.  The  organism  separates  at  these 
places  and  the  process  begins  over  again.  Under  the  higher  powers 
of  the  microscoj>e  bright  shining  spots  appear  within  the  protoplasm 
of  the  germ  cells,  which  are  the  new  spores  or  life  forms  which  will, 
under  suitable  conditions,  increase  and  break  away  from  the  parent 
cell  and  develop  into  full  grown  cells  themselves,  and  these  spots 
will  again  appear  within  their  walls,  and  so  the  multiplication  goes 
on  until  the  conditions  become  unfavorable  for  their  nourishment. 
These  favorable  conditions  depend  of  course  on  the  amount  of  ma- 
terial exposed  to  their  action,  and  the  temperature  sufficiently  warm 
for  their  vegetating  power,  which  for  the  great  numbers- of  bacteria 
must  be  from  60°  to  90°  F.,  but  there  are  some  exceptions  among 
the  alcoholic  ferments  where  the  temperature  can  fall  to  36°  or  38^ 
F.  The  conditions  favorable  to  the  propagation  also  depend  on  the 
compounds  formed  by  their  own  action  on  the  particular  substrata 
which  they  are  causing  to  ferment.  Sometimes  an  acid  is  generated 
which  will  kill  them,  and  that  acid  may  be  due  to  their  own  action. 
The  condition  will  become  favorable,  too,  when  the  organisms  have 
performed  their  work.  Other  forms  may  appear  and  take  up  the 
work  of  disintegration  where  the  first  form  left  oflf,  and  so  after  these 
forms  have  fulfilled  their  work,  still  others  may  appear  on  the  new 


14 


BACTERIOIvOGY  IN  CANNING. 


mtdium  so  formed  and  find  it  favorable  to  their  peculiar  action.  Dur- 
ing the  process  of  germination  any  particular  form  of  bacillus  may 
change  in  character  from  its  peculiar  form  as  known  under  ordi- 
nary conditions.  A  rod  shaped  bacterium  may  assume  the  shape  of 
a  curved  form  like  the  spirillum  or  thread-like  as  the  leptothrix 
and  round  like  the  coccus.  These  various  forms  of  the  same  bac- 
terium have  caused  considerable  trouble  in  classification,  because 
they  may  have  the  appearance  of  a  different  variety  or  specie.  The 
figure  No.  2  will  give  some  idea  of  the  different  forms  of  bacteria. 


^  <^ 


Figure  2. 


a— GERMINATION  OF  SPORES, 
b— BACTERIA  WITH  ELGEI.I,A. 
C— SPORE  FORMING  CEI/I*S. 
d— ZOOGI.OEA. 

e— cocci. 


f— DIPI.0C0CCI. 
g— STREPTOCOCCI  OR  CHAINS, 


SPIRII,I.A  AND  VIBRIOS. 
-I.EPTROTHRIX. 


When  germination  takes  place  by  spores  the  appearance  of  the 
mother  germ  darkens  and  appears  granular  when  a  certain  point 
becomes  prominent  and  it  swells  rapidly,  using  up  the  protoplasm 
of  the  cell  in  forming  the  new  growth.  Sometimes  the  former  cell 
will  not  expand  again,  but  appears  to  dry  up,  in  which  case  the  life 
is  maintained  in  the  spore  which  still  clings  to  the  mother  cell.  In 
a  suitable  fermentable  substance,  the  spore  will  germinate,  first 
swelling  to  unusual  size,  when  the  spore  within  will  burst  through 

See  Figure  4. 


BACTERIOLOGY  IN  CANNING.  15 

the  wall  and  there  will  appear  two  germs  where  formerly  only  one 
was  visible. 

There  are  anthrospore  and  endospore  forms  of  bacteria.  The 
endospore  bacteria  form  their  spores  on  the  inside  of  the  plasma  or 
wall  of  the  cell,  while  the  anthrospore  bacteria  do  not.  The  zoogloea 
forms  of  bacteria  are  peculiar  to  slimy  formations,  so  that  when  you 
observe  any  fluid  of  a  ropy  nature,  as  sometimes  happens  with  peas, 
it  is  this  form  of  bacteria  largely  the  cause  of  such  action,  but  there 
are  of  course  other  reasons  for  ropiness  in  canned  peas.  These 
bacteria  grow  very  fast  in  colonies  almost  pure  naturally. 

The  spore  formation  of  the  yeast  plant,  saccharomyces,  is  most 
interesting.  The  view  of  these  cells  budding  as  seen  under  a  power 
of  1000  diameters  in  the  microscope,  is  most  interesting  because 
they  can  be  seen  so  plainly,  and  their  appearance  is  beautiful.  In 
fact  the  microscope  opens  up  a  new  world  in  the  vegetable  kingdom 
and  the  study  is  most  fascinating. 


Figure  3. 

I  took  a  quantity  of  filtered  tomato  juice  and  placed  a  culture  of 
these  alcohol  ferments  in  it,  and  the  next  day  I  transferred  a  single 
drop  under  the  cover  glass,  filling  the  slight  excavation  and  laying 
the  cover  glass  over  this  to  prevent  to  a  certain  extent  the  evapora- 
tion of  the  liquid.  I  located  a  few  cells  and  watched  them  closely ;  I 
detected  shining  spots  within  the  cell  walls  which  appeared  to  be 
swelling.  After  a  time  I  was  awarded  by  seeing  a  slight  protuber- 
ance on  one  side  of  a  cell  which  increased  rapidly  in  size,  remaining 
attached  to  the  parent  cell.  After  a  time  other  cells  began  budding, 
and  then  I  noticed  that  the  first  bud  had  fully  developed  and  was  in 
its  turn  showing  signs  of  germination.  In  a  short  time  it  sent  out  a 
bud  and  the  mother  sent  out  another  one  in  the  opposite  direction. 
In  a  few  hours  I  again  examined  the  view  and  the  beautiful  scene 
was  laid  out  before  me  as  the  following  illustration  will  show.  All 
this  occurred  in  a  field  not  larger  than  a  pin  point,  and  no  doubt 


i6  BACTERIOLOGY  IN  CANNING. 

would  have  been  much  more  abundant  in  development  if  the  oxygen 
had  not  been  partially  cut  off  by  the  cover  glass.  I  then  glued  the 
cover  glass  fast  to  the  glass  slide,  and  in  a  very  short  time  the  glass 
burst  from  the  pressure  of  the  carbonic  acid  gas  which  was  being 
liberated  freely.  There  appeared  also  other  forms  of  bacterial  life 
from  the  atmosphere  in  zoogloeas  and  the  lactic  bacteria  were  also 
visible,  appearing  in  little  short  rods. 

The  spores  of  the  saccharomyces,  as  I  stated,  began  to  show 
themselves  within  the  wall  of  the  cell,  and  exerted  such  a  pressure 
in  swelling  as  to  push  through  the  wall,  and  after  sending  out 
several  buds  would  turn  dark  and  appear  to  shrivel  up.  I  met  also 
with  cells  which  sent  out  buds  which,  when  developed,  would  break 
away  from  them  entirely.  I  examined  all  these  specimens  in  a  tem- 
perature of  70°  to  80°  F.,  which  probably  accounts  for  the  appear- 
ance of  other  forms  in  the  illustration.  The  true  alcohol  ferments 
may  be  cultivated  almost  pure  at  a  temperature  of  36^  to  40^  F.,  and 
while  their  development  is  slow,  they  are  able,  however,  to  accom- 
plish fermentation,  without  the  interference  of  other  organisms 
which  will  not  vegetate  excbpt  in  higher  temperatures.  This  pecu- 
liarity of  the  yeasts  make  the  brewing  of  beer  comparatively  easier 
than  the  ol3  method  where  little  attention  was  paid  to  temperatures. 

A  peculiar  film  appeared  on  the  tomato  juice  that  I  spoke  of 
before,  and  gradually  became  thicker  and  wrinkled  in  appearance, 
and  the  saccharomyces  seemed  to  stop  their  action  and  settle  down 
to  the  bottom  of  the  glass.  I  examined  the  fiim  under  the  micro- 
scope and  recognized  it  as  the  mycoderma  cerevisiae  and  myco- 
derma  vini,  and  I  found  that  this  film  was  using  up  all  the  free 
oxygen  from  the  air  and  so  depriving  other  germs  of  that  very  essen- 
tial element.  The  cells  are  various  shaped,  some  round,  some  long 
and  almost  transparent.  The  spores  are  easily  seen  and  have  a  rest- 
less movement  within  the  walls  of  the  cell.  This  form  is  quite  com- 
mon and  appears  on  the  surface  of  many  of  the  fruit  juices. 


fop  ^ 

0 


^  ^  <y    (z> 


&  p 


MYCODERMA  VINI  AND   CEREVISIAE. 


V*  OF   THK  1^ 

UNIVERSITY 


Figure  4 
MAGNIFIED  X  1000. 


\ 

BACTERIOLOGY  IN  CANNING.  17 

The  growths  of  the  mold  fungi  are  also  interesting,  because 
we  can  see  them  with  the  naked  eye  to  attain  the  height  of  an  inch 
sometimes.  They  have  a  characteristic  plant  form  and  thrive  on  all 
liquids  of  a  slightly  acid  nature,  especially  fruit  juices.  The  first 
mold  I  will  describe  with  reference  to  its  growth,  is  the  pencillium 
glaucum,  which  starts  from  a  spore  sending  out  long  branches 
which  have  the  appearance  of  lengthening  out  and  dividing,  like 
the  branches  of  a  bush  with  joints.  When  these  grow  to  a  certain 
height  the  tuft  branches  produce  a  large  number  of  conidia,  so  that 
the  whole  surface  of  a  patch  of  the  pencillium  glaucum  will  be 
covered  with  millions  of  these  little  round  cells,  each  of  which  is 
able  to  start  a  new  plant  whenever  it  falls  upon  a  suitable  medium. 
As  a  body  they  present  a  grayish  blue  color,  and  look  smaller  than 
the  yeast  germs. 


I  ^.0^ 


Figure  6. 
PENCILLIUM  GLANCUS. 

a— CONIDIA. 

b  — CONIDIA  SENDING  OUT  A  BRANCH. 

C— REPRESENTS  THE  BRANCHES  WITH  CONIDIOPHORES  AND  THESE  BEAR- 
ING  NEW   CONIDIA  OR   ROUND   CEI.LS   WHICH   ARE  SEED. 

d— CONIDIOPHORE  WITH  THE  SPORES  OF  THE  CONIDIA,  BEFORE  THE  CEI«I« 
WAI.I,  IS  RUPTURED. 

ASPERGILLUS  GLAUCUS. 

Aspergillus  glaucus  is  a  mold  fungus,  somewhat  ?.milar  to  the 
pencillium  in  the  manner  of  its  development  and  production  of 
conidia.  Its  peculiarity  i§  the  spiral  forms  of  its  ascogonium,  which 
is  enveloped  by  the  hyphae.  This  is  a  very  common  variety  of 
mold  w^hich  grows  in  abundance  in  damp  places. 

MUCOR  RACEMOSUS. 

This  is  a  mold  fungus  which  grows  at  ordinary  temperatures 
on  acid  surfaces  of  fruit  juices,  or  in  any  damp  place  where  a  fer- 
mentable substratum  is  a  base  of  growth.     This  fungus  grows  luxu- 


i8  BACTERIOLOGY  IN  CANNING. 

riantly  on  bread  and  attains  a  considerable  height.  The  branches 
and  sporangia  have  about  the  same  characteristics  in  their  forma- 
tion of  spores  that  the  two  former  ones  have,  that  we  have  studied. 
In  addition,  this  fungus  has  the  power  to  propagate  by  budding, 
resembhng  in  many  respects  the  true  yeast  fungi.  The  spores  are 
colorless.  When  mucor  racemosus  is  submerged  in  a  fermentable 
liquid  the  sections  appear  to  swell  and  become  large  and  oval 
shaped,  filled  with  a  highly  refractive  plasma.  They  separate  at  the 
lines  of  demarkation  and  begin  budding.  The  conidia  or  spores 
have  the  same  characteristic  and  resemble  the  saccharomyces  very 
much.  They  sometimes  germinate  in  this  way  when  cultivated  on  a 
solid  substratum. 

MONILIA  CANDIDA. 

This  fungus  is  a  white  or  grayish  colored  mold  which  grows 
from  the  spore  just  the  same  as  the  other  varieties  we  have  ex- 
amined, and  pear  shaped  or  elliptical  spores  form  on  the  ends  of  the 
branches.  It  is  found  on  sweet,  juicy  fruits,  and  when  submerged 
will  produce  alcoholic  fermentation  and  will  form  a  white  film  on 
the  top  of  fruit  juices. 


^^/? 


Figure  7. 
MAGNIFIED  X  1000. 

a-  MONILIA   GROWING  WHEN    SUBMERGED, 
b— MONILIA  CELLS  OF  A  FILM  FORMATION. 


Figure  8. 
MAGNIFIED  X  looo. 


BACII^IvUS   I^ACTICI   ACIDI-SOUP  SUBSTRATUM. 


CHAPTER  IV. 

BACTERIA   COMMONLY   FOUND   IN   DECOMPOSING   FRUIT   AND  VEGE- 
TABLES.     MICROSCOPICAL    VIEWS   AND   DESCRIPTIONS 
CHAR  ACTERISTICS . -—STERILIZATION . 

It  is  not  my  purpose  at  this  time  to  take  up  a  complete  list  of 
the  various  bacteria  found  in  the  many  kinds  of  fruit  products,  but 
only  a  few  of  the  more  common  varieties,  in  order  that  the  reader 
may  become  familiar  with  these  forms  and  understand  clearly  what 
is  meant  when  we  speak  of  them  in  the  following  pages. 

LACTIC  ACID  BACTERIA. 

This  form  of  bacteria  as  seen  under  a  microscope  of  looo  x 
appears  in  short  rods  slightly  contracted  in  the  middle,  as  will  be  seen 
by  the  representation  below. 

It  will  resist  very  high  temperatures,  and  it  requires  at  least 
250°  F.  for  ten  to  fifteen  minutes  to  kill  the  dry  forms. 

They  are  the  forms  which  commonly  cause  milk  to  turn  sour, 
but  are  found  everywhere  in  fermenting  fruit  juices,  and  act  very 
readily  on  the  milk  of  corn.  The  above  view  was  taken  of  a  culture 
of  these  germs  transferred  to  a  drop  of  com  milk  and  placed  under 
a  microscope.  Their  action  is  directly  on  the  sugar  contained  in  the 
milk  and  they  convert  it  into  lactic  acid  with  no  carbonic  acid  gas 
when  acting  alone.  They  are  rarely  if  ever  found  acting  alone,  how- 
ever, and  it  is, only  by  making  pure  cultures  that  they  may  be 
studied  for  a  short  time  under  the  glass.  Other  forms  will  make 
their  appearance  very  soon.  This  form  of  bacteria  flourishes  very 
rapidly  at  a  temperature  of  80^  to  90°  F.  It  grows  on  gelatine  plates 
as  small,  white  points,  becoming  opaque,  forming  a  thick  layer.  The 
colonies  appear  dark  yellow  in  the  middle.  This  is  one  of  the  species 
of  bacteria  which  are  found  acting  on  nearly  all  kinds  of  food  pro- 
ducts and  has  considerable  resisting  power  to  high  temperatures. 

BUTYRIC    ACID  BACTERIA. 

Clostridium  butyricum  and  amylobacter  are  the  putrefactive 
ferments  which  cause  a  great  deal  of  trouble  in  the  canning  indus- 


20  BACTERIOLOGY  IN  CANNING. 

try.  This  form  is  one  of  the  most  resistant  to  high  temperatures, 
and  develops  spores  which  are  hard  to  kill.  These  spores  are  found 
in  dried-up  forms  clinging  to  the  fresh  product,  and  will  begin  to  de- 
velop whenever  a  suitable  medium  presents  itself. 

These  bacteria  act  on  the  sugar  producing  butyric  acid,  car- 
bonic acid  and  hydrogen,  and  they  are  anaerobic,  producing  a  very 
unpleasant  taste  in  fruit  juice.  It  is  a  motile  organism  and  looks  Hke 
a  short  straight  rod.  When  these  bacteria  are  ready  to  form  spores 
they  swell  up  into  peculiar  shapes,  spindle,  club  shape,  lemon  shape 
and  elliptical.  The  spores  burst  the  outer  protoplasm  and  begin  de- 
veloping into  a  new  organism.  When  colored  by  iodine  the  butyric 
bacteria  appear  blue.  They  develop  rapidly  at  blood  heat.  In  gela- 
tine they  form  yellow  colored  colonies.  I  consider  this  form  of 
bacteria  to  be  one  of  the  most  dangerous  forms  to  be  met  with  in 
the  canning  of  corn  and  peas.  The  full  grown  bacillus  is  easily  killed 
at  the  boiling  temperature,  but  the  spores,  especially  the  dried-up 
forms  that  have  been  floating  in  the  air  when  they  find  a  lodgment 
in  the  milk  of  the  corn,  are  very  hard  to  kill.  They  are  so  small  in 
this  dried-up  form  that  we  can  almost  conceive  of  them  being  able 
to  pass  through  the  juice  without  becoming  wet.  After  milk  has. 
soured  by  the  action  of  the  lactic  bacteria,  and  the  acid  is  neutral- 
ized by  lime,  it  will  set  up  butyric  fermentation  caused  by  the 
butyric  ferments.  This  is  a  spontaneous  butyric  fermentation  from 
the  bacteria  in  the  atmosphere,  and  will  start  at  a  temperature  of 
70^  to  80^  F.  The  butyric  ferments  act  very  readily  on  starch,  dex- 
trine, dextrose  and  sugar  cane.  These  bacteria  also  play  a  very  im- 
portant part  in  the  ripening  of  cheese  and  give  it  its  peculiar  flavor. 
They  have  the  power  of  decomposing  fermentable  substances  with- 
out the  aid  of  free  oxygen,  and  on  this  account  we  terrri  them 
anaerobic.  The  following  view  will  give  some  idea  how  they  ap- 
peared in  a  view  taken  of  fermenting  com  milk.  The  rods  repre- 
sent the  bacilli  and  the  dots  represent  the  spores. 

ACETIC  ACID  BACTERIA. 

The  two  well  known  forms  of  bacteria  which  cause  acetic  acid 
are  the  mycoderma  aceti  and  the  bacterium  Pasteurianum.  In  183S 
Turpin  and  Kutzing  discovered  that  acetic  acid  fermentation  was 
caused  by  micro-organisms,  and  Pasteur  in  1864  confirmed  the  cor- 
rectness of  their  assertion  and  called  the  organism  mycoderma 
aceti,  but  as  he  was  not  working  with  any  particular  culture,  he  did 
not  bring  out  the  fact  that  this  acid  could  be  produced  by  at  least 
one  other  form,  if  not  more.   As  he  did  not  employ  pure  cultures. 


Figure  9. 
MAGNIFIED  X  1000. 


BACILIyUS  BUTYRICUS. 


^t£BE  L/8^ 


Ol'  THl 


SITY 


Figure  lo. 
MAGNIFIED  X  looo. 


BACII.LI   BUTYRICI— SHOWING  SPORES. 


BACTERIOLOGY  IN  CANNING.  21 

his  methods  of  making  vinegar  were  not  used  practically,  and  in 
1879  Hansen  classified  the  germs  and  obtained  pure  cultures.  The 
''quick  vinegar  process"  is  employed  in  the  manufacture,  where  the 
liquid  is  divided  into  drops  and  given  free  access  to  the  atmosphere 
and  given  free  distribution  over  large  surfaces  of  beech  shavings, 
where  the  process  is  taken  up  and  completed  by  the  organisms. 
The  acetic  acid  germs  are  characterized  by  long  chains  of  hour- 
glass shape,  partially  bacilli  and  curved  forms.  Mycoderma  aceti 
are  stained  yellow  by  iodine,  while  bacteria  Pasteuriana  are  given 
a  blue  color  by  the  same  stain.  No  spores  have  been  seen  in  these 
bacteria. 


Figure  11. 

MYCODERM  ACETI  AND  BACTERIA  PASTEURIANA. 

The  bacteria  are  present  in  large  numbers  in  various  fruit  and 
vegetable  juices,  and  are  so  common  everywhere  in  the  atmosphere 
that  they  are  among  the  earliest  forms  of  organic  life  to  appear  in 
the  fermentation  of  food  products. 

BACII«I.US  VISCOSUS 

We  will  now  take  up  the  study  of  a  form  of  bacteria  which 
plays  a  great  part  in  the  spoiling  of  canned  goods,  especially  of 
vegetables  like  peas,  beans,  asparagus  and  corn,  causing  the  whole 
liquid  part  to  become  slimy  and  ropy  so  that  it  can  be  lifted  in  long 
sticky  threads.  The  varieties  or  species  of  this  slime  producing 
bacteria  are  given  the  name  of  bacilli  viscosi.  They  have  the  power 
of  resisting  high  temperatures  which,  of  course,  makes  sterilization 
difficult. 

It  is,  of  course,  very  necessary  to  know  the  characteristics  of 
such  forms  of  bacterial  life,  their  forms,  resisting  power  with  refer- 
ence to  heat  and  antiseptics  and  their  probable  source,  in  order  to 
guard  against  them  as  much  as  possible  at  the  time  when  the  pro- 


22 


BACTERIOLOGY  IN  CANNING. 


duct  is  exposed  to  their  action.  You  have,  no  doubt,  seen  cans  of 
various  kinds  of  vegetables  opened  and  found  the  liquid  part  ropy 
and  slimy,  when  to  all  appearances  it  was  clear  when  filled  into  the 
can.  This  trouble  has  caused  the  packers  of  peas  no  end  of  worry, 
because  they  have  not  taken  into  consideration  that  much  of  this 
trouble  was  due  to  this  kind  of  a  bacterium.  There  are  some  people 
who  put  up  a  great  deal  of  molasses  in  tin  cans,  and  have  a  great 
deal  of  trouble  in  preventing  fermentation,  especially  during  the  hot 
summer  months. 

The  fermentation  set  up  by  this  organism  is  very  violent, 
especially  when  deprived  of  free  oxygen.  It  forms  carbonic  acid  gas 
in  great  pressure,  even  to  the  extent  of  bursting  cans  tested  to  with- 
stand 50  to  75  pounds  pressure.  Bacilli  viscosi  make  slimy  patches 
in  molasses  and  sets  up  this  fermentation,  and  on  account  of  its  re- 
sisting power  to  sterilization,  it  is  hard  to  keep  molasses  in  tins  dur- 
ing the  hot  weather,  because  high  temperatures  deteriorate  the 
quality  of  the  goods. 

This  organism  causes  the  same  trouble  in  wine  and  beer,  which 
we  sometimes  see,  become  ropy.';:The  organism  forms  in  clusters 
resembling  zoogloea  as  the  envelopment  in  the  slime  formation 
holds  them  in  clusters.  Pasteur  discovered  these  bead-like  chains 
which  set  up  a  viscous  fermentation  with  carbonic  acid  gas  when 
introduced  in  wine  and  beer,  and  Van  Laer  found  bacilli  in  rods 
forming  zoogloea,  which  produced  the  same  viscous  fermentation. 
This  fermentation  and  slime  formation  is  great  in  proportion  to  the 
quantity  of  nitrogenous  matter  in  the  liquid.  Ordinarily  the  cocci 
appear  in  pairs  surrounded  by  an  envelope  of  mucilaginous  matter. 
They  sometimes  grow  without  the  gelatinous  envelope,  and  so  ap- 
pear when  cultivated  on  potato. 


<P  Co 


0      "  ^ 

sQ    DOoOOOOOoOrt 

^   ^    /    9 


8 
3 


C 


Figure  12. 
MAGNIFIED  X  1000. 

BACILI,!  VISCOSI. 


:eesE  Os^ 


thh 


^>?^ 


University 


Figure  13 
MAGNIFIED  X  1000. 

ONE   PART   BOUILLON,    99   PARTvS   WATER.     RANK    PUTREFACTION,    BOUIL- 
LON,   PRODIGIOvSI. 


BACTERIOLOGY  IN  CANNING.  23 

The  manner  of  protecting  food  products  from  this  scavenger 
and  the  requirements  necessary  for  steriHzing  vegetable  and  fluids 
where  it  finds  a  lodgment,  will  be  taken  up  under  the  process  em- 
ployed in  canning  and  preserving  as  they  will  be  described  in  pages 
to  follow,  and  under  those  heads  we  will  endeavor  to  clear  up  some 
of  the  mysteries  of  spoilage. 

BACII,I,US  PRODIGIOSUS. 

This  is  the  organism  which  gives  the  odor  of  herring  brine  or 
fish  to  putrefying  substances,  and  is  also  named  bleeding  bread, 
because  it  is  a  pigment  bearing  bacillus  of  red  color,  and  forms 
spots  when  growing  on  bread,  potatoes  and  onion  that  resemble 
blood.  It  is  an  egg-shaped  germ  about  uuiui^  of  an  inch  in  diame- 
ter, which  is  very  small.  It  has  no  motion  and  multiplies  by  divi- 
sion. It  is  so  minute  as  to  be  barely  perceptible  with  a  power  of  1000 
diameters,  and  Ehrenberg  calculated  that  a  cubic  inch  would  con- 
tain one  quadrillion.  This  organism  is  very  common,  nearly  always 
associated  with  decomposition  of  vegetable  matter  in  putrefactive 
stages.  One  peculiarity  about  this  bacillus  is  that  at  blood  heat  it 
fails  to  produce  the  red  pigment  and  peculiar  fish  odor,  but  at  60^ 
to  70°  F.,  when  cultivated  on  agar,  both  of  these  characteristics  are 
evident.  The  drawing  here  represented  was  taken  from  life. 

Prodigiosus  has  the  property  of  converting  fermenting  sub- 
stances of  a  fermentable  nature  into  lactic  acid  at  a  temperature  oi 
80°  to  90*^  F.,  at  which  temperature  it  produces  no  red  pigment, 
so  that  the  whole  of  its  energy  is  employed  in  the  fermenting  pro- 
cess. When  milk  is  soured  and  lactic  acid  is  produced,  it  sometimes 
has  a  blue  color,  which  is  a  pigment  in  the  protoplasm  of  a  bac- 
terium, similar  in  many  respects  to  the  bacillus  prodigiosus. 
Bacillus  prodigiosus  is  also  a  germ  causing  unsoundness  in  bread 
and  bakers  have  to  guard  their  dough  against  this  action  to  pre- 
vent souring  before  the  baking.  In  manufacturing  tomato  catsup 
and  various  condiments  where  chopped  onions  are  used,  it  is  ad- 
visable to  keep  them  in  cool  places  or  use  them  ag  soon  after  chop- 
ping as  possible,  to  avoid  discoloration  and  flavor  injury  from  the 
action  of  this  bacterium. 

SACCHAROMYCES    APICUI^ATUS. 

This  is  a  lemon-shaped  bacterium  and  is  one  of  the  few  germs 
which  have  a  peculiar  form  easily  recognized  wherever  we  meet  them. 
They  always  appear  on  the  juice  of  sweet  juicy  fruits  when  exposed 


24  BACTEPJOLOGY  IN  CANNING. 

to  the  atmosphere.  The  buds  are  either  lemon  shaped  or  round. 
The  first  view  I  had  of  these  pecuHar  forms  of  organic  Hfe  was  on  a 
substratum  of  pineapple  juice  to  which  had  been  added  a  small 
quantity  of  sugar,  and  left  exposed  to  the  atmosphere.  In  a  short 
time  a  fermentation  set  in  which  was  not  unpleasant  to  the  taste. 
Examination  under  the  microscope  revealed  a  pure  culture  of  these 
bacteria,  and  the  scene  was  one  of  the  prettiest  I  have  ever  ex- 
amined. The  little  lemon-shaped  cells  were  sending  out  buds 
rapidly,  and  the  juice  had  a  flavor  of  alcohol  so  similar  in  many 
respects  to  the  yeast  plant  fermentations,  but  its  power  to  produce 
alcohol  is  only  about  one-sixth  of  that  produced  by  the  yeast 
saccharomyces  cerevisiae.  It  is  found  in  abundance  during  fruit 
seasons  on  cherries,  grapes,  plums,  gooseberries,  pineapples,  etc., 
on  the  ripe  fruits,  ready  to  begin  action  as  soon  as  the  juice  is  ex- 
posed. It  is  always  found  in  the  soil  under  the  trees  and  bushes  of 
such  fruits,  probably  on  account  of  having  flourished  on  fallen 
fruit  and  carried  down  into  the  ground  by  rains;  remaining  alive 
all  through  the  winter.  In  the  summer  time  it  is  carried  by  wind 
or  dust,  and  falling  upon  the  fruit  still  growing,  remains  until  it 
ripens  before  setting  up  fermentation.  This  characteristic  ferment 
to  this  kind  of  fruits,  its  habits,  its  habitation,  and  last  its  lodgment 
on  the  fruit  which  makes  its  existence  possible,  is  only  an  example 
of  almost  every  other  form.  Each  form  will  be  found  in  dose 
proximity  to  its  victim,  and  nearly  all  fruits  and  vegetables  and 
other  things  will  have  the  dried-up  forms  either  on  them  or  near 
them,  ready  when  the  time  comes  to  resolve  the  substance  again  to 
elementary  forms.  This  is  the  great  scheme  of  nature  to  make  old 
things  new  again,  and  reduce  the  matured  things  of  earth  to  ele- 
ments to  furnish  nutriment  for  the  new. 

'  Although  there  are  many  other  bacteria  which  make  their  ap- 
pearance in  fermentable  substances,  we  have  described  a  few  of  the 
more  important  as  having  to  do  with  the  canning  and  preserving 
industries,  and  they  are  the  principal  forms  we  meet,  and  if  we 
guard  against  them,  we  need  have  no  fears  about  other  forms,  ex- 
cepting, perchance,  a  bacterium  like  the  bacillus  subtilis  and  the 
bacillus  panificans  should  make  their  appearance,  in  which  case  the 
entire  method  of  canning  would  have  to  be  changed  in  order  to  keep 
the  goods  from  fermenting.  So  resistant  to  heat  are  the  spores  of 
these  two  forms,  and  I  have  no  doubt  other  unclassified  forms,  that 
they  can  withstand  temperatures  of  300°  F.  for  hours,  and  then  de- 
velop and  cause  fermentation.  So  far  as  I  know,  these  forms  have 
not  made  their  appearance  in  articles  or  products  which  are  canned 


Figure  14 
MAGNIFIED  X  1000. 


SACCHAROMYCBS   APLCUI.ATUS   ON    PINEAPPI^E  JUICE. 


Wf.-^ 


^ 


>/\ 


^v*"^ 


Figure  15. 
MAGNIFIED  X   1000. 

BACII^UUS  SUBTII.IS   WITH  ENDOSPORES   X    lOOO  ON   BOUII.I.ON. 


BACTERIOIvOGY  IN  CANNING.  25 

and  preserved.  It  might  be  well,  however,  to  give  a  sketch  of  these 
two  forms,  for  fear,  perhaps,  they  might  at  no  distant  time  find  a 
place  among  the  scavengers  of  canning  products. 

BACILI^US  SUBLII^IS. 

This  bacillus  is  spore  bearing,  and  the  spores  appear  to  be 
special  protoplasmic  cells,  developed  in  the  parent,  surrounded  by 
a  thin  but  very  hard  membrane,  and  it  is  this  membrane  which  pro- 
tects the  life  of  the  spore  against  the  action  of  heat  and  antiseptics 
before  development  into  full  grown  bacilli.  Dry  heat,  of  course, 
would  be  less  efficacious  than  moist  heatj  because  the  latter  if  ap- 
plied in  certain  ways  will  soften  the  membrane  and  cause  the  pro- 
toplasm within  to  swell,  at  which  time  the  germ  is  most  susceptible 
to  high  temperatures.  When  moist  heat  is  applied  it  is  noticed  that 
the  protoplasm  becomes  dark  and  granular,  where  before  it  was 
clear  and  transparent,  and  it  then  begins  to  swell  and  gradually  will 
stretch  the  membrane  until  it  bursts  across  the  middle,  which  dis- 
tinguishes this  form  from  the  bacillus  amylobacter,  which  bursts 
its  membrane  lengthwise.  After  bursting  the  membrane  it  makes  its 
way  out  and  begins  to  vegetate  by  lengthening  and  dividing  across 
the  rod  form,  at  which  time  heat  of  160^  F.  will  kill  them.  This 
bacterium  makes  its  appearance  in  hay  infusions  that  have  been 
boiled,  and  it  is  the  organism  that  caused  Professor  Tyndail  so 
much  trouble  in  trying  to  sterilize  the  infusions  on  account  of  its 
great  resisting  power  to  heat.  It  is  a  motile  organism  about  ^^,^7^ 
of  an  inch  long  and  jziffs  of  an  inch  in  diameter.  Its  spores  are 
large  and  easily  studied.  It  multiplies  very  fast,  producing  much 
carbonic  acid  gas  and  seems  to  be  peculiar  to  hay. 

Owing  at  times  to  the  close  proximity  of  hay  fields  to  land 
where  the  cultivation  of  canning  products  is  carried  on,  it  would  not 
surprise  me  at  any  time  to  find  this  organism  flourishing  in  corn, 
peas,  beans,  etc.,  in  which  case  a  complete  change  of  processing 
would  become  necessary  in  order  to  keep  these  articles  from  fer- 
menting. In  that  case  the  present  sterilizing  process  would  be  use- 
less, and  new  methods  based  entirely  on  bacteriological  knowledge 
would  have  to  take  their  place.  The  system  referred  to  will  be 
taken  up  in  detail  under  another  head,  and  people  who  desire  to  be 
progressive  can  find  a  method  laid  down  to  form  the  base  of  ex- 
periments that  ultimately  will  insure  a  superior  quality  and  perfect 
sterilization. 

The  bacillus  panificans  is  another  spore-bearing  bacillus  which 


26  BACTERIOLOGY  IN  CANNING. 

is  very  resistant  to  the  action  of  high  temperatures.  The  bacilli 
themselves,  like  the  bacilli  subtilis  and  butyrici,  are  easily  killed 
at  less  than  boiling  temperature,  212^  F.,  but  the  seed  form,  the 
spores,  are  very  resistant  and  cannot  be  killed  by  continuous  boil- 
ing, notwithstandng  any  statement  made  to  the  contrary.  These 
statements  are  made  by  some  scientists  who  claim  to  have  killed 
the  spores  in  half  an  hour  by  boiling,  but  they  either  were  dealing 
with  other  forms  or  kinds  of  bacteria,  or  they  never  did  what  they 
claimed.  We  know  that  Tyndall  tried  this,  and  we  have  his  word  to 
the  contrary,  and  our  own  experience  with  corn  and  peas,  etc., 
bears  him  out.  I  have  tried  time  after  time  to  kill  these  forms  by 
boiling  for  eight  hours,  and  every  experiment  broke  down.  So  the 
spores  of  panificans  cannot  be  killed^by  boiling.  This  is  the  organ- 
ism which  sets  up  the  fermentation  of  the  dough  of  rye  bread,  and 
is  peculiar  to  r}^e.  It  is  a  short  mptiJe 'rod  with  threads  which  in- 
terlace to  form  a  film  when  grown  "on  liquid  media.  So  far  as  I 
know  these  two  forms,  subtilis  and  panificans,  do  not  as  yet  enter 
into  the  catalogue  of  ferments,  which  cause  the  troubles  in  canning 
and  preserving  of  food  products. 

CHAPTER  V. 

PATHOGENIC  BACTERIA.      STUDIED   BECAUSE  OF  THE   POISONS   PRO- 
DUCED WHEN   ACTING   ON   FOOD   PRODUCTS.    DIFFERENT  KINDS 
OF   THESE  BACTERIA   STUDIED.      THEIR    ACTION   ON 
VARIOUS   FOOD   PRODUCTS 
DESCRIBED. 

We  have  been  describing  bacteria  of  non-pathogenic  character,, 
viz :  The  ordinary  forms  and  organisms  which  cause  fermentation 
of  food  products,  but  which  have  no  connection  with  the  diseases  of 
man.  While  it  is  true  that  ordinary  ferments  when  causing  fer- 
mentation, if  taken  into  the  stomach,  will  cause  stomach  disorders, 
and  sometimes  violent  sickness,  they  must  not,  however,  be  con- 
flicted with  organisms  which  cause  specific  diseases  in  man.  It  is 
not  our  purpose  in  a  work  of  this  character  to  take  up  a  complete 
history  of  all  known  forms  of  diseases  and  the  organisms  which 
cause  them,  but  simply  to  study  those  forms  which  in  atmospheric 
fermentation  find  a  lodgment  in  food  products  of  albuminous 
nature,  and  by  their  action  on  the  albumens  produce  alkaloids  and 
toxic  poisons  which  come  under  the  generic  name  of  ptomaines. 

In  a  preceding  chapter  (page  21)  we  have  taken  up  the  sub- 
ject of  ptomaines  and  called  attention  to  the  very  common  occur- 


JSTUBR^ 


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UNIVERSITY 
CALIFQ^ 


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Figure  i6. 
MAGNIFIED  X  looo. 

CHOLERA  GERMS  IN  COMMA,  S  SHAPED  AND  O  SHAPED  FORMS. 


BACTERIOLOGY  IN  CANNING.  27 

rence  of  poisoning  from  these  alkaloids,  and  a  description  of  some 
of  the  organisms  must  be  interesting.  The  study  of  these  forms 
carries  the  student  in  bacteriology  into  a  very  difficult  field,  from 
the  fact  that  the  character  of  these  organisms,  their  mode  of  action, 
etc.,  is  removed  from  the  ordinary  field  of  fermentation,  and  while 
their  action  is  fermentative  in  character,  they  are  so  frequently  found 
deep  in  the  tissue  of  the  muscles  of  the  sufferer  that  they  become 
anaerobic  in  nature,  and  hard  to  cultivate  in  an  aerobic  state  on 
mediums  prepared  by  artificial  means. 

Many  forms,  however,  occur  so  abundantly  in  nature  that  they 
can  be  cultured  and  studied,  and  these  forms,  with  possibly  one  or 
two  exceptions,  fall  into  the  line  of  our  study  here. 

COMMA  BACCILI.US— CHOI.ORA. 

The  ptomaines,  cadaverine,  putrescine  and  choline  are  without 
doubt  the  result  of  this  deadly  germ,  which  has  started  a  fermenta- 
tion on  albuminoids.  The  comma  bacillus  was  discovered  by  Dr. 
Koch  to  be  the  cause  of  Asiatic  cholera,  and  it  is  due  to  this  bril- 
liant scientist  that  the  mysteries,  doubts  and  difficulties  surrounding, 
this  dreaded  pestilence  have  been  cleared  up.  It  was  proved  that 
the  germs  were  carried  in  railways,  caravans  and  ships  from  Lx)wer 
Bengal  in  the  delta  of  the  Ganges  to  all  parts  of  the  world,  although, 
this  organism  is,  no  doubt,  present  in  every  section  of  the  globe. 
It  does  not,  however,  break  out  into  epidemics  like  those  occurring 
in  Asia,  except  in  very  rare  cases.  The  section  of  country  men- 
tioned is  the  regular  hot  bed  for  the  disease,  and  it  is  epidemic  there 
frequently,  owing,  no  doubt,  to  imperfect  sanitary  measures. 

The  comma  bacillus  belongs  to  the  class  of  spirilla,  or  curved 
bacteria,  and  usually  occurs  in  slightly  curved  rods  measuring  from 
1  At  to  2  /A  of  an  inch  in  length  and  about  .5  /*  of  an  inch  ia 
thickness.  It  occurs  sometimes  in  pairs,  sometimes  in  the  shape  o£ 
letter  S.  Frequently  they  assume  the  shape  of  serpentine  threads. 
The  bacillus  is  identified  by  placing  some  of  the  substance  on  which 
they  grow  on  the  glass  slide  under  the  microscope  and  allowing 
a  weak  solution,  methyl  violet,  to  flow  between  the  cover  glass  and 
slide,  taking  up  the  overflow  by  blotting  paper.  With  an  oil  im- 
mersion lens  of  1000  diameters  they  may  be  observed  alive. 

They  may  be  easily  recognized  by  their  vigorous  movement 
and  the  stain  from  the  color  which  they  take  up.  They  will  grow 
and  multiply  rapidly  on  prepared  meat  broth  kept  at  blood  heat 
in  an  incubator,  and  in  time  grow  larger  and  form  spirilla. 


28  BACTERIOLOGY  IN  CANNING. 

Chemical  examination  and  analyses  of  this  broth  will  show  the 
presence  of  the  ptomaine  poisons  mentioned  at  the  beginning  of 
this  section.  Babes  found  that  at  a  temperature  of  blood  heat,  the 
bacillus  would  grow  on  various  kinds  of  meat,  on  eggs,  vegetables 
and  moistened  bread,  on  cheese,  coffee,  chocolate  and  fluid  sugars, 
but  only  feebly  on  acid  fluids  or  vegetables,  on  mustard,  onions, 
wine,  beer  or  distilled  water.  Wherever  there  is  a  large  quantity  of 
organic  matters,  as  at  the  margin  of  stagnant  water,  they  would 
thrive.  Milk  is  one  of  the  most  dangerous  agencies  for  the  growth 
of  the  bacilli,  and  has  caused  the  death  of  many  persons  who  have 
used  it. 

The  comma  bacillus  is  an  aerobic  organism,  but  does  not  cease 
to  multiply  if  the  supply  of  oxygen  is  cut  off,  but  may  under  this 
condition  be  killed  readily  by  germicidal  agencies,  while  in  the 
aerobic  state  they  are  very  resistant  to  such  agencies.  But  when  the 
supply  of  oxygen  is  cut  off  it  produces  a  much  larger  proportion 
of  toxic  poisons  than  when  oxygen  is  present,  on  account  of  the 
necessity  of  acting  on  a  much  larger  quantity  of  albuminous  mat- 
ter in  order  to  get  the  oxygen  necessary  to  its  reproduction. 

One  fact  relating  to  this  organism,  as  well  as  all  other  organ- 
isms we  have  been  considering,  is  that  freezing  does  not  kill  them 
as  they  seem  to  pass  through  a  dormant  state,  and  will  develop  on  a 
suitable  medium  at  favorable  temperatures.  One  experiment  by 
Koch  on  these  bacilli  at  — lo^  C.  did  not  kill  them,  and  they  de- 
veloped rapidly  when  placed  in  favorable  conditions.  The  early  ob- 
servations on  ptomaines  and  sepsines,  Pasteur's  and  Hansen's  later 
observations,  led  to  a  search  for  finding  the  poisonous  properties, 
or  rather  results  of  the  action  of  comma  bacilli.  Koch  prepared 
cultures  of  these  organisms  which  were  very  poisonous,  and  when 
given  to  animals  in  any  way  caused  their  death — "paralytic  weak- 
ness of  the  lower  extremities,  coldness  of  head  and  legs  and  pro- 
longed respiration,  leading  to  death."  Pouchet  and  Villiers  were 
able  to  obtain  substances  from  the  action  of  the  comma  bacilli  on 
the  dejecta  and  organs  of  cholera  patients  which  were  characteristic 
of  the  organism. 

Pouchet  used  chloroform  and  extracted  an  extremely  toxic 
poison  in  the  nature  of  an  oily  fluid  which  changed  colors  in  the 
presence  of  light  and  air.  His  substance  gave  the  characteristic 
reaction  of  the  alkaloid,  the  blue  reduction  color  with  ferrocyanide 
and  perchloride  of  iron.  Villiers  also  separated  an  alkaloid  from  the 
dejecta  of  a  cholera  patient  which,  when  treated  with  muriatic  acid, 
formed  crvstals,  which,  when  chemically  combined  with  other  com- 


UNIVERSITY 
CALIFOBii^ 


Figure  17. 
MAGNIFIED  X  1000. 

TYPHOID   BACItLT   IN   CI^USTER   FOUND    IN   A  GI.AND   IN  THE   INTESTINES. 
•  FROM   REAI,  MICROSCOPIC   VIEW. 


BACTERIOLOGY  IN  CANNING.  29 

pounds,  produced  a  caustic  local  action  and  muscular  troubles  and 
an  irregular  heart  action,  and  finally  death.  Brieger  was  able  to  find 
several  poisons,  especially  from  cultures  of  the  bacillus  which  were 
old,  which  were  choline,  cadaverine  and  putrescine.  He  went  into 
these  researches  very  far;  he  obtained  a  toxic  poison  which,  when, 
injected  into  animals,  produced  muscular  tremors,  cramps  and 
death.  He  named  this  new  product  methyl-guanidine.  He  also  sepa- 
rated two  other  toxines  characteristic  of  the  cholera  bacillus.  All 
these  experiments  were  made  with  pure  cultures  of  the  comma 
bacillus,  and  the  toxines  found  were,  of  course,  in  much  larger  pro- 
portions than  when  found  in  natural  growths  on  suitable  media- 
Experiments  with  these  natural  growths,  however,  give  practically 
the  same  results,  proving  that  the  comma  bacillus  is  capable  of 
producing  the  most  deadly  ptomaines. 

One  peculiar  feature  in  the  study  of  this  deadly  organism  is 
that  it  does  not  exert  a  rapid  fermentation  where  other  common 
ferments  and  non-pathogenic  putrefactive  organisms,  have  obtained 
a  hold.  Indeed,  we  can  state  that  these  other  forms  would  isolate 
the  comma  bacillus  and  cause  it  to  perish,  because  certain  acids 
would  be  produced  by  their  action  which  would  act  as  antiseptics, 
to  it,  and  this  is  true  where  almost  all  other  pathogenic  forms  ap- 
pear outside  of  the  body.  Once  in  a  while,  however,  under  favorable 
conditions,  it  happens  that  the  cholera  germ  will  begin  action  first 
and  produce  a  ptomaine  before  other  common  forms  would  get  a 
hold  on  the  product.  In  this  case,  should  the  substance  happen  to 
be  a  food  product  of  an  albuminous  nature  and  taken  into  the  stom- 
ach at  any  time  after  the  organism  had  produced  the  toxic  alkaloid, 
serious  muscular  tremors  and  cramps  would  result,  perhaps  ending- 
in  death. 

TYPHOID  BACILLUS. 

The  typhoid  fever  germ  when  growing  in  meat  broth  and  albu- 
minoids produces  a  ptomaine  which  has  been  isolated  by  Brieger 
and  called  typhotoxin,  and  it  is  on  this  account  that  .we  take  up 
the  study  of  this  organism.  The  bacilli  are  short,  thick  rods  from 
Ts-^jijf  to  TsUs  of  an  inch  in  length  and  about  one-fourth  of  their 
length  in  thickness.  They  have  slightly  rounded  ends,  and  the  pro- 
toplasm is  susceptible  to  color  by  aniline  dyes.  They  also  may  be 
stained  by  allowing  them  to  stand  in  a  solution  of  oxalic  acid,  and 
after  washing  will  take  a  methyl  blue  color.  The  typhoid  germ  is 
found  in  the  kidneys,  spleen  and  intestines  of  fever  patients,  in  colo- 
nies or  clusters  widely  separated,  which  sometimes    makes    then* 


JO  BACTERIOLOGY  IN  CANNING. 

difficult  to  locate.  Cultivated  they  assume  a  thread-like  appearance, 
with  flagella,  which  gives  them  a  wavy  motion.  The  germ  is  able 
.to  flourish  in  either  an  aerobic  or  anaerobic  state,  exhibiting  the 
same  peculiarities  as  the  comma  bacilli,  in  that,  when  growing  in 
the  presence  of  oxygen  they  are  very  resistant  to  the  action  of 
germicides  and  heat,  and  produce  less  toxic  poison  than  when  grow- 
ing in  an  anaerobic  state,  requiring  the  decomposition  of  more 
albuminous  substance  to  obtain  enough  oxygen  for  their  multi- 
plication. 

The  typhoid  bacilli  grows  rapidly  on  potato,  where  they  assume 
typical  forms,  because  the  potato  is  slightly  acid,  which  is  a  neces- 
:sary  characteristic  for  their  propagation. 

Unlike  many  other  forms,  this  germ  seems  to  form  an  acid 
poison  instead  of  an  alkaloid  poison.  It  develops  rapidly  in  milk 
.and  also  in  water  containing  decaying  albuminous  matter.  When 
cultures  of  this  bacillus  were  given  to  animals  in  food  they  soon^ 
died,  but  was  found  that  the  bacteria  need  not  be  alive  to  cause 
•death.  Any  substance  which  had  been  exposed  to  their  action 
would  also  cause  death  when  reaching  the  intestines,  and  the  cause 
was  traced  to  toxic  and  ptomaine  poisoning  which  Brieger  proved 
wrere  present  in  the  substances. 

These  organisms  are  visibly  afifected  by  light  and  grow 
htst  in  dark  or  shady  places.  Rays  of  sunlight  or  chemical  rays 
are  very  injurious  to  their  development.  This  is  true  of  nearly  all 
pathogenic  forms,  and  it  would  seem  to  indicate  that  the  rays  of 
light  seem  to  shoot  them,  to  use  a  military  term,  and  it  is  hoped 
that  the  development  and  improvement  of  the  X-rays  will  begin  to 
-open  up  a  new  method  of  destroying  these  dreadful  enemies  of  man. 
It  is  a  dreadful  thing  to  contemplate,  that  there  are  organisms  so 
minutely  formed  which  can  find  their  way  into  the  body  and  use  the 
tissue  to  build  up  poisons  so  fatal.  We  can  now  see  that  it  is  not 
•so  much  the  germ  itself  which  causes  the  death  of  man  as  it  is  the 
poison  deposited  by  the  germ  deep  in  the  tissue  which  paralyzes 
•the  muscles^and  stops  the  heart  from  beating. 

These  organisms  also  build  up  the  same  poisons  in  the  very 
food  we  eat  when  proper  conditions  present  themselves,  and  were 
it  not  for  the  fact  that  man  is  fortified  against  them,  by  counteract- 
ing influences  and  secretions  of  the  body,  we  would  all  fall  victims 
one  by  one  to  their  deadly  action.  Nor  can  we  say  that  we  will 
escape  finally,  but  so  long  as  we  know  the  enemies  and  can  take 
proper  precautions  against  them,  by  removing  from  our  midst 
those  decaying  things  on  which  they  grow,  eat    and    drink    pure 


Figure  18. 
MAGNIFIED  X  1000. 

TETANUS  BACII.I.I. 


BACTERIOLOGY  IN  CANNING.  31 

food  and  water,  observing  every  sanitary  rule,  we  can  at  least  keep 
the  enemy  in  check  until  age  has  weakened  our  energies  and  we 
finally  have  to  face  the  inevitable.  Like  the  plant  and  the  beast, 
nature  will  claim  us  all,  our  bodies  will  form  the  food  for  this  in- 
significant germ  and  we  will  pass  away  to  be  dissolved  again  into 
elementary  forms. 

What  a  study  it  is  then,  this  science  of  bacteriology.  It  opens 
up  a  new  world  to  us  and  we  are  permitted  to  gaze  upon  it  and 
behold  the  scheme  of  nature  giving  us  object  lessons  day  by  day 
in  the  tearing  down  and  building  up  process.  Life  begetting  new 
life,  and  new  life  flourishes  on  the  dead.  Seed  developing  into 
form,  form  producing  seed,  decay  of  form,  and  development  of  seed. 
This  is  true  of  the  germ  and  also  of  every  living  thing. 

TETANUS. 

The  tetanus  bacillus  produces  specific  poisons  which  have 
been  found  and  isolated,  viz :  tetanine,  tetanotoxin  and  two  other 
alkaloids  resembling  strychnine. 

Tetanus  is  an  infective  disease,  a  wound  fever,  and  known  as 
lockjaw,  and  is  produced  by  a  micro-organism  which  fincjs  its  way 
into  a  wound  and  sets  up  a  muscular  disease  by  producing  poison- 
ous alkaloids.  This  organism  is  found  in  the  pus  of  the  abscess  and  in 
the  surrounding  tissue.  It  is  a  thread  shape  bacillus  with  slightly 
rounded  ends.  The  spores  are  formed  at  the  end  of  a  short  rod  and 
develop  at  blood  temperature  after  thirty  hours.  When  the  spores 
form  on  these  short  rods,  which  are  motile,  the  bacillus  resembles 
a  drum  stick.  It  is  a  strongly  anaerobic  organism,  as  the  presence 
of  oxygen  interferes  with  its  development,  and  this  fact  has  made 
it  a  difficult  matter  to  obtain  pure  cultures.  Cultivations  are  made, 
however,  in  an  atmosphere  of  hydrogen. 

Brieger,  to  whom  we  owe  much  of  our  knowledge  of  the  tox- 
ines  and  ptomaines,  which  are  the  poisonous  alkaloids  produced 
by  the  pathogenic  organisms,  found  the  poisons  peculiar  to  this 
germ,  which  he  describes  as  tetanine  and  tetanotoxin.  From  the 
fact  that  this  is  an  anaerobic  organism  it  is  surprising  on  first 
thought  how  it  could  gain  a  hold  in  a  wound  where  oxygen,  of 
course,  is  present,  but  when  the  spores  of  this  organism  find  a  lodg- 
ment in  a  wound,  where  proper  precautions  have  not  been  taken, 
the  pus  and  blood  corpuscles  soon  cover  them  and  cut  off  the 
oxygen  of  the  air.  Here  then  the  conditions  are  favorable  for  the 
development  of  the  tetanus  bacillus.  Tetanus  bacilli,  or  more 
properly  their  spores,  are  very  common  and  are  found  everywhere, 


32  BACTERIOLOGY  IN  CANNING. 

in  the  soil  and  around  horses,  particularly.  They  seem  to  be  found 
more  numerously  around  stables,  in  manure  and  the  soil  which 
has  been  manured.  Vaillard  and  Vincent  made  careful  observations 
of  the  results  of  the  tetanus  bacillus,  and  having  separated  the 
poison,  found  that  it  acted  very  similar  to  snake  poison.  They  found 
that  the  bacilli  did  not  produce  poison  only  after  acting  for  quite 
a  time.  In  the  presence  of  other  organisms  of  putrefactive  nature, 
such  as  lactic  acid  bacilli  and  prodigiosi,  they  produce  the  poison 
much  more  quickly.  This  peculiarity  of  the  organism  is  a  striking 
contrast  to  the  other  forms  we  have  been  considering,  because  the 
acids  of  the  common  putrefactive  organisms  usually  have  a  germi- 
cidal action  on  pathogenic  forms.  Even  small  quantities  of  this 
poison  if  present  in  any  food  will  set  up  the  most  terrible  muscu- 
lar tremors  and  cramps,  followed  by  sure  death,  as  there  is  no 
known  antidote.  It  is  a  peculiar  fact,  however,  that  we  are  fortified 
to  some  extent  against  this;  organism  before  the  poison  is  formed  in 
the  wound;  the  blood  corpuscles  in  healthy  tissue  generally  de- 
stroy it.  This  organism  then  is  dangerous  to  man  if  it  happens  to 
find  a  lodgment  in  any  food  product,  especially  in  canned  meats 
and  goods  of  an  albuminous  nature,  where  the  packages  are  sealed 
hermetically,  producing  anaerobic  condition  so  favorable  for  its 
reproduction,  and  also  from  the  fact  that  it  is  able  to  produce 
ptomaines  more  rapidly  when  acting  along  with  other  putrefactive 
micro-organisms. 

Stanley  in  his  travels  through  Africa  gives  a  bit  of  peculiar 
and  interesting  information  which  we  can  readily  trace  to  the  action 
of  this  organism.  He  found  that  the  savages  in  certain  sections 
poisoned  their  arrow  points  by  covering  them  first  with  a  nutrient 
juice  of  a  tree,  then  taking  them  to  a  place  where  drainage  had 
accumulated  decomposing  substances,  they  stuck  them  in  the  soil,, 
allowing  them  to  remain  for  a  considerable  time.  These  arrows 
would  set  up  the  most  violent  muscular  contractions,  followed  by 
lockjaw  and  death  whenever  they  found  a  lodgment  in  the  flesh  of 
their  enemies.  This  poison  was,  no  doubt,  caused  by  the  formation 
of  an  alkaloid  poison  by  the  tetanus  bacilli. 

We  are  of  the  opinion  that  poisons  in  food  products  from  this 
peculiar  organism  do  not  generally  occur  in  foods  that  are  exposed 
to  the  air,  but  only  in  hermetically  sealed  packages.  We  frequently 
hear  of  some  one  being  poisoned,  sometimes  whole  families  stricken 
after  having  eaten  certain  kinds  of  canned  meats,  and  we  feel  as- 
sured that  this  organism  produces  some  of  the  poisons  which  cause 
these  complications.    It  is  likely  that  its  action  takes  place  after 


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BACTERIOLOGY  IN  CANNING.  33 

the  can  has  been  sealed,  before  the  final  sterilizing  process,  which 
destroys  their  life,  but  not  the  product  of  that  life.  This  trouble 
is  due  to  carelessness,  the  result  of  ignorance  of  the  deadly  nature 
of  these  organisms,  and  this  carelessness  is  the  allowing  of  too  much 
goods  to  pile  up  ahead  of  the  final  process. 

KI^EBS-I^O^FFI^KR.  BAC1I,I,US— DIPHTHERIA. 

The  diphtheria,  or  Klebs-Loefifler  bacillus,  when  growing  on 
suitable  media,  produces  a  most  virulent  ptomaine,  which  Brieger 
isolated  and  used  in  various  experiments  upon  animals,  which 
caused  a  poisoning  similar  to  septic,  phosphorous  and  metallic 
poison.  On  this  account,  many  cases  of  poisoning  from  eating  sub- 
stances like  ice  cream  and  certain  kinds  of  meat,  fish,  etc..  (which 
were  due  to  a  ptomaine,  where  the  action  resembled  metallic  poison- 
ing), were  at  first  thought  to  come  from  the  metal  packages  which 
contained  the  foods.  As  a  matter  of  fact,  however,  the  agent  was 
a  bacillus  similar,  if  not  identical  with  the  Klebs-Loeffier  bacillus. 
The  suspected  metals  are  not  so  poisonous  as  many  persons  im- 
agine, as  they  are  found  in  many  vegetables.  Copper  is  found  in  the 
tomato  in  some  sections,  and  other  vegetables  contain  metals  also. 
One  eminent  authority  has  gone  so  far  as  to  state  that  the  system 
is  not  affected  by  the  presence  of  metals  in  small  quantities  in 
food  products.  The  poison  that  does  cause  the  trouble  in  these 
food  products  is  an  alkaloid  produced  by  micro-organisms,  such  as 
the  diphtheria  bacillus.  That  this  organism  produces  a  most  viru- 
lent poison  is  undisputed  from  the  fact  that  the  fatality  from  the 
specific  disease  is  very  great.  As  has  been  stated  in  former  pages 
the  chances  of  these  pathogenic  forms,  for  acting  on  food  products, 
are  very  rare  in  comparison  to  the  action  of  common  ferments,  but 
occasionally  they  get  a  start,  and  when  they  do,  we  are  informed 
of  the  fact  by  the  terrible  consequences  produced  on  the  innocent 
victims.  It  is  only  as  a  word  of  warning  to  packers  and  preservers 
that  we  have  taken  up  this  subject,  to  point  out  where  the  danger 
exists,  and  to  make  a  few  suggestions,  which  may  by  careful  ob- 
servation, preclude  the  possibiHty  of  these  cases  of  poisoning  in  the 
canning  business,  where  even  a  few  cases  of  this  kind  causes  op- 
position and  prejudice  against  canned  goods  generally.  Whenever 
a  case  of  this  kind  occurs  it  hurts  the  entire  business,  and  we  must 
take  unusual  precautions  to  guard  against  them.  But  to  return  to 
our  sul)]ect,  the  Klebs-Loefifler  bacilli  are  rods  from  3  fi  to  6  fi 
of  an  inch  in  length,  slightly  swollen  at  one  or  both  ends,  and  are 
colored  easily  with  methyl  blue,  or  by  Gram's  gentian  violet  method. 


34  BACTERIOLOGY  IN  CANNING. 

It  is  recognized  from  other  bacilli,  which  may  be  present,  by  the 
deep  stain  which  it  takes  in  contrast  to  the  lighter  stains  taken  by 
other  forms.  It  is  a  difficult  organism  to  cultivate  in  a  pure  form, 
as  other  putrefactive  ferments  get  started  first  and  overgrow  the 
media.  It  thrives  at  a  very  high  temperature,  and  the  spore  forms 
will  live  in  the  air  and  on  the  clothing  for  a  long  time.  It  produces 
an  alkaline  poison  which  loses  toxic  properties  when  made  acid, 
and  gains  back  the  properties  when  made  alkaline  again.  Milk  is 
susceptible  to  the  action  of  this  germ,  also  any  food  of  an  albumin- 
ous nature,  but  the  toxic  power  is  lost  in  the  presence  of  the  com- 
mon ferments,  which  nearly  always  gain  a  foothold  first  and  pro- 
duce their  acids,  which  have  a  tendency  to  neutralize  the  ptomaine 
which  it  produces. 

It  must  not  be  understood  that  the  varieties  we  have  men- 
tioned in  the  foregoing  sketches  of  pathogenic  organisms  include  all 
the  kinds  that  produce  ptomaines.  It  is  undoubtedly  true  of  many 
others,  among  which  we  might  mention  the  anthrax  bacilli  and 
organisms  which  cause  septicaemia,  but  the  products  of  all  these 
forms  are  very  similar  in  their  action,  producing  severe  muscular 
contractions,  cramps,  paralysis  and  death.  By  studying  their  nature 
we  may  to  some  extent  understand  the  Ufe  history  of  these  forms 
and  the  poisons  which  they  create  by  their  action  on  food  pro- 
ducts. It  is  this  knowledge  which  will  enable  us  to  pack  and  pre- 
serve food  products  and  eliminate  these  forms  so  that  no  poisons 
will  be  deposited  in  them.  It  is  a  very  fortunate  thing  that  their 
action  is  confined  to  food  products  of  an  albuminous  nature,  as  this 
represents  only  a  small  proportion  of  our  business.  The  greater 
number  of  packers  and  preservers  confine  their  preserving  to 
vegetables  and  fruits,  while  the  greater  bulk  of  albuminous  pro- 
ducts are  packed  by  comparatively  few  canners.  We  refer  here  to 
packers  of  beef,  fish,  oysters,  lobsters  and  soups,  and  it  is  to  these 
packers  that  the  history  of  the  ptomaines  as  here  detailed  should 
be  very  interesting  and  instructive.  The  greatest  danger  in  all  these 
varieties  comes  in  warm  weather,  when  the  thermometer  ranges 
about  blood  heat.  These  products  when  exposed  for  only  a  very 
short  time  to  the  atmosphere  offer  the  most  suitable  medium  for 
the  propagation  of  putrefactive  ferments  of  all  kinds,  including,  of 
course,  the  pathogenic  organisms.  It  is  a  peculiar  fact  that  the  most 
favorable  time  for  these  organisms  to  gain  a  foothold  is  after  the 
first  cooking,  because  it  so  rapidly  develops  the  spores,  or  dried- 
up  forms  which  may  find  a  lodgment  there.  The  heat,  of  course,  is 
the  reason  for  this  and  the  anaerobic  forms  will    develop    rapidly 


BACTERIOLOGY  IN  CANNING.  35 

after  the  cans  are  sealed  if  they  be  not  taken  immediately  to  the 
final  process  for  sterilization.  Once  more  we  must  sound  the  warn- 
ing that  all  goods,  whether  vegetable  or  albuminous  in  character, 
should  find  their  way  immediately  to  the  retorts  after  the  first 
heating.  Here  is  where  the  greatest  trouble  to  all  packers  occurs; 
something  breaks  down  about  the  machinery  and  the  consequence 
is  that  many  dozens  of  cans  will  pile  up  which  have  within  them  the 
spores  of  germs  deposited  from  the  air  or  perhaps  dinging  to  the 
product  from  the  beginning.  At  so  favorable  a  temperature  for  the 
development  of  these  spores,  a  delay  for  only  a  short  time  is  in- 
imical to  the  quality.  Fermentation  begins  to  set  in  almost  im- 
mediately, and  the  most  wonderful  growths  of  bacterial  forms  can 
take  place  in  a  very  short  time,  which  will  change  the  very  nature 
of  the  goods,  producing  new  chemical  combinations  and  some- 
times very  poisonous  combinations,  as  we  have  seen.  We  do  not 
pretend  to  say  that  this  is  the  only  place  where  ptomaines  could  be 
formed  in  the  albuminous  products,  but  it  is  one  of  the  most  dan- 
gerous places.  A  great  deal  depends  on  the  management,  that  when 
breakdowns  occur,  other  means  of  taking  care  of  the  goods  should 
be  provided  at  once.  It  is  not  policy  to  limit  a  business  to  the  exact 
number  of  machines  necessary  to  do  the  work  when  everything 
runs  smoothly,  but  to  be  prepared  for  emergencies  of  this  kind, 
which  always  happen,  even  in  the  best  managed  business,  by  hav- 
ing one  or  two  extra  machines  which  can  be  utilized  at  such  times. 

We  can  see  where  great  dangers  from  ptomaine  poisoning 
might  present  themselves  at  earlier  stages  in  the  canning  process. 
The  canner  should  be  provided  with  experienced  and  cautious  men, 
and  by  that  I  mean  men  who  have  studied  up  on  the  subject  which 
we  are  here  presenting.  The  diseases  peculiar  to  the  animals  and 
fish,  the  meats  of  which  are  canned,  may  deposit  ptomaines  in  the 
living  tissue,  as  we  often  read  of  as  occurring  in  cattle,  fowls,  pork, 
etc.  The  Government  understands  the  full  gravity  of  this  question 
by  having  inspectors  for  all  meats  appointed  in  different  cities. 
If  diseased  animals  should  be  slaughtered  and  the  meat  of  those 
animals  find  its  way  into  cans,  the  possibility  of  ptomaine  poisoning 
among  the  consumers  of  such  goods  would  be  great.  To  the  per- 
sonal knowledge  of  the  writer,  schemes  have  been  imposed  on  the 
inspectors  and  meat  has  been  canned  which  was  wholly  unfit  for 
food  purposes.  This  was  done  simply  with  the  one  idea  to  save 
the  cost  of  the  meat,  while  probably  the  fearful  results  were  never 
suspected.  Packers  who  are  engaged  in  canning  products  of  an 
albuminous  nature  should  be  very  careful  that  they  are  entirely 


36  BACTERIOIvOGY  IN  CANNING. 

free  from  anything  that  would  resemble  disease  in  any  form. 
No  amount  of  cooking  or  pickling  will  counteract  the  effect  of  this 
poison,  it  remains  because  it  is  a  new  chemical  compound,  an  alka- 
loid or  an  acid.  We  see  the  effect  of  this  poison  by  frequent  ac- 
counts of  persons  who  have  eaten  smoked  fish,  mainly  halibut  and 
sturgeon,  and  also  fresh  sausage  which  have  become  poisoned  by 
pathogenic  micro-organisms. 

This  subject  of  ptomaine  poisoning  is  a  very  recent  discovery, 
and  its  full  import  has  not  been  felt  until  within  the  last  few  years, 
owing,  perhaps,  to  the  large  increase  in  the  mortaHty  of  persons 
using  products  sealed  in  hermetical  packages.  The  number  of 
deaths  has  increased  in  proportion  to  the  increased  packing  of 
goods  of  this  character,  and  it  is  with  the  hope  of  reducing  this 
mortality  that  these  researches  have  been  given  in  such  minute 
detail. 


CHAPTER  VI. 

FERMKNTATION.      OBJECT  OF  STUDY  IS  TO  PREVENT.      AI,COHOI,IC 
FERMENTATION  AND  THE  GERMS  WHICH    CAUSE  IT.      PUTRE- 
FACTION.     DISEASE  FERMENTATION.      PRODUCTS  OF  FER- 
MDNTATION.      DESCRIPTIVE   EXAMPI.ES.      ENZYMES. 
I.ACTIC  FERMENTATION.      BENEFITS  TO    PI.ANT 
AND   ANIMAI.   JJFE.      FERMENTATION   DE- 
FINED  IN   A   BROAD  SENSE. 

In  order  to  understand  definitely  the  action  of  micro-organ- 
isms, their  Hfe  history,  functions  and  products,  we  must  take  up  the 
subject  of  fermentation,  not  with  the  same  object,  however,  as 
brewers  and  wine  makers,  but  with  a  view  of  counteracting  the 
process.  The  canning  and  preserving  industries  are  established 
for  the  sole  purpose  of  keeping  food  products Jn  a  perfectly  sterile 
and  healthful  condition  for  food  purposes.  Alcoholic  fermentation' 
is  the  kind  which  is  set  up  by  the  saccharomyces  or  yeast  plants, 
of  which  there  are  a  great  variety,  but  only  a  few  kinds  are  used  in 
the  brewing  business,  mainly  those  which  produce  the  greatest 
amount  of  alcohol.  Then  there  is  the  putrefactive  fermentation,, 
caused  by  various  kinds  of  organisms,  chiefly  of  a  lower  form  than 
the  saccharomyces,  and  it  is  their  organisms  which  reduce  the  de- 
composing animal  and  vegetable  matter  into  elementary  forms. 

Then  there  is  the  disease  fermentation  which  is  set  up  in  the 
living  tissues  of  man  and  animals  by  the  pathogenic  organisms,  and 
they  deposit  poisons  which  produce  various  diseases  and  death. 


BACTERIOLOGY  IN  CANNING.  37 

Taken  as  a  whole,  fermentation  is  the  breaking  down  process, 
a  reduction  of  the  higher  forms  of  Ufe  to  elementary  forms.  When^ 
a  fermentable  substance  is  exposed  to  the  atmosphere  it  is  seized 
upon  immediately  by  various  organisms.  These  are  deposited  in 
<iried-up  forms,  called  spores.  These  spores  are  seeds  just  like 
a  grain  of  com  is  a  seed  of  the  full-grown  stalk,  and  they  will  de- 
velop by  vegetation  into  their  normal  condition  and  will  bear  again 
the  same  kind  of  spores  or  seed.  There  are  some  organisms,  how- 
ever, which  do  not  bear  spores,  but  which  multiply  by  division, 
simply  lengthening  out  and  dividing  in  two,  while  the  life  principle 
seems  to  be  contained  in  the  cell  walls,  which,  in  a  vegetating  state, 
are  swelled  or  distended  and  filled  with  a  protoplasm  to  which  has 
been  given  the  name  plasma. 

Now  when  these  spores  find  their  way  into  our  fermentable 
medium  they  do  not  all  begin  to  vegetate,  but   only   those   forms 
which  have  an  affinity  for  that  particular  medium,  of  which  therp 
may  be  quite  a  number  of  different  varieties.    They  may  not  all 
begin  vegetating  at  once,  we  may  have  an  alcoholic  fermentation 
set  up  first,  which  means  that  if  the  medium  is  suitable  for  that  par- 
ticular fermentation,  the  sugar  will  be  broken  up  into  alcohol,  car- 
bonic acid  gas,  glycerine,  succinic  acid,  etc.   After  this  the  alcohol 
may  be  seized  upon  by  other  forms,  such  as  acetic  acid  bacteria, 
which  will  convert  it  into  acetic  acid.     Again  the  butyric  and  lactic 
ferments  may  begin  their  action  directly  on  the  sugar  and  convert 
it  into  butyric  and  lactic  acids.    We  now  have  the  nature  of  our 
nutrient  medium   entirely  changed,  chemical  changes  have  been 
made,  the  atoms  of  one  set  of  molecules  have  gone  to  make  up  new 
molecules,  and  old  molecules  deprived  of  part  of  their  atomical 
structure  form  new  compounds,  similar  in  many  respects  symbol- 
lically,  but  entirely  different  in  character.  To  demonstrate  what  we 
mean  by  fermentation  we  will  take  an  example  which  will  instruct 
us  by  its  simplicity."    If  we  take  a  great  number  of  blocks  of  wood, 
such  as  a  child  uses  for  building  houses,  and  we  erect  a  tall,  square 
pile,  we  will  have  something  of  definite  shape  which  we  can  call 
by  a  single  name  such  as  a  house  or  a  wall.  Now  if  we  pull  out  from 
the  bottom  one  or  two  blocks,  we  change  the  center  of  gravity  and 
we  have  some  of  the  upper  blocks  standing  in  a  weakened  position. 
Their  power  of  holding  together  has  become  less.    We  can  com- 
pare the  starting  of  fermentation  to  the  nutrient  medium,  the  same 
as  the  weakening  influence  given  to  the  pile  of  blocks  by  the  re- 
moval of  the  two  at  the  base.  If  we  pull  out  another  block  we  may 
observe  the  pile  begin  to  waver,  and  by  the  removal  of  another  one 


38  BACTERIOLOGY  IN  CANNING. 

whole  corner  falls.  This  example  will  demonstrate  the  action  of  the 
organisms  on  one  part  of  our  medium.  Now  if  we  remove  from 
another  part  of  our  pile  still  other  blocks  we  will  soon  have  the 
whole  thing  lying  in  ruins.  With  our  nutrient  medium  other  organ- 
isms will  take  up  the  work  of  destruction  where  the  first  ones  left 
off,  and  soon  the  whole  combination  will  be  upset.  As  one  writer 
has  given  another  example  to  explain  fermentation,  we  will  take 
the  liberty  of  using  the  same  here.  It  is  a  well  known  fact  that  the 
great  explosive  power  of  nitroglycerine  is  due  to  the  unstableness 
of  its  atomical  arrangement.  Some  oxygen  has  been  induced  to 
unite  with  nitrogen,  a  substance  for  which  under  ordinary  circum- 
stances it  has  little  affinity,  it  having  at  the  same  time  a  much 
stronger  affinity  for  both  carbon  and  hydrogen  than  these  have 
for  each  other ;  rapid  and  extensive  oscillations  are  constantly  going 
on,  the  slightest  increase  of  which  must  be  followed  by  a  new 
arrangement  of  molecules.  A  shock  so  increases  these  oscillations 
that  the  molecular  equilibrium  is  disturbed,  the  weak  bands  be- 
tween the  oxygen  and  nitrogen  are  severed  and  the  free  oxygen 
is  immediately  pounced  upon  by  the  carbon  and  the  hydrogen, 
which  are  set  free  from  one  another,  each  of  these  elements  taking 
up  a  certain  quantity  of  the  freed  oxygen;  the  atoms  of  nitrogen 
having,  of  course,  a  strong  affinity  for  one  another,  combine  and  a 
small  portion  of  oxygen  is  set  free.  The  amount  of  energy  released 
is  very  great  indeed,  and  it  is  the  more  readily  observed  and  even 
measured  from  the  fact  that  the  process  goes  on  rapidly  and  vio- 
lently, as  it  usually  does  where  the  resolution  is  that  of  a  very 
complex  body,  into  extremely  simple  substances.  Now  let  us  see 
what  takes  place  when  sugar  is  converted  into  alcohol  and  carbonic 
acid  gas.  When  the  yeast  plant  begifis  to  act  or  set  up  fermenta- 
tion we  notice  an  immediate  gradual  increase  of  temperature,  which 
may  be  likened  to  the  tap  that  caused  the  nitroglycerine  to  explode, 
the  molecules  are  set  to  oscillating  by  the  temperature  and  the  heat 
also  brings  about  the  proper  temperature  for  the  perfect  vegetation 
of  the  cells,  and  it  is  a  deduction  from  what  we  have  seen,  that  heat 
and  moisture  are  very  necessary  in  the  process  of  fermentation. 
These  two  conditions  must  be  always  present,  one  without  the  other 
will  not  give  the  result.  Pasteur  says:  "Fermentation,  properly 
so-called,  can  be  looked  upon  as  a  chemical  phenomenon,  co- 
relative  with  physiological  actions  of  a  peculiar  nature,  in  this  sense, 
that  bacteria  have  the  property  of  exercising  all  the  functions  of 
their  life,  not  excepting  negative  multiplication  without  necessarily 
employing  the  oxygen  of  the  air.     Guided  by  all  these  facts,  I  have 


BACTERIOLOGY  IN  CANNING.  39 

been  gradually  led  to  look  upon  fermentation  as  a  necessary  con- 
sequence or  manifestation  of  life  when  that  life  takes  place  with- 
out the  direct  combustion   due  to  free  oxygen."    Thus  we  are 
brought  face  to  face  with  one  great  fact ;  that  is,  that  not  only  are 
bacteria  able  to  cause  the  fermentation  of  sugar  and   setting   free 
carbonic  acid  gas,  but  fruits,  vegetables,  grain,  etc.,  have  the  same 
property,  possessing  within  themselves  the  power  to  cause  the  fer- 
mentation of  the  natural  sugar  present  in  them,  and  sugar  which 
may  be  introduced.  We  thus  see  that  the  process  is  brought  about 
by  living  cells,  and  the  kind  of  fermentation  set  up  depends,  of 
course,  on  the  nature  of  these  cells  and  also  on  the  nature  of  the 
fermentable  substance.    The  yeast  plants  or  saccharomyces  have 
the  power,  when  acting  on  sugar,  to  produce  alcohol,  carbonic  acid 
gas,  witli  other  substances,  viz :  succinic  acid,  glycerine,  etc.,  which 
vary  in  proportion  to  the  kind  of  substance  that  these  organisms 
are  causing  to  ferment.    Various  flavors  are  also  imparted  to  the 
different  fermentable  substances;  for  instance,  the  flavor  which  is 
imparted  to  the  beer  and  wine,  and  the  peculiar  flavor  of  cheese  and 
butter  we  know  is  due  to  the  products    of    the    butyric    ferment, 
amylobacter.    It  will  not  be  necessary  for  us  in  this  work  to  take 
up  the  study  of  any  particular  yeast  fungus,  or  to  classify  these 
forms,  as  that  is  interesting  only  in  the  industries  of  wine  and  beer 
making.    There  have  been  various  works  which  have  taken  up  the 
study  of  the  various  saccharomyces,  and  these  works  are  used  by 
brewers  and  wine  makers  with  an  object  entirely  different  from  our 
object,  as  they  need  pure  cultures  of  these  organisms  in  their  busi- 
ness, while  our  object  is  to  eliminate,  not  only  these  forms,  but  all 
others.    As  a  matter  of  fact  the  saccharomyces  cause  the  canner 
and  preserver  very  little  trouble,  unless  it  be  in  the  products  before 
canning.   They  are  very  susceptible  to  heat  and  perish  even  in  the 
first  cooking.   There  is  one  form  of  fermentation,  however,  similar 
in  many  respects  to  the  fermentation  caused  by  the  yeast  fungi, 
which  is  a  constant  menace  to  our  business.  We  refer  to  that  caused 
by  mold.   This  statement  will,  no  doubt,  be  a  surprise  to  the  can- 
ner, because  he  has  always  regarded  mold  as  a  fungus  growth  which 
did  not  play  any  part  in  the  destruction  of  his  product.  The  conidia 
of  mold  are  the  spore  formations  which  develop  at  the  ends,  or  more 
properly  on  the  top  of  the  fungi.  These  spores  have,  by  actual  ex- 
periment,   lived .  through    a   temperature    of    300°    F.,    dry   heat, 
but   have   not    been    able    to   withstand    so    high    a    temperature 
in  moist  heat.   When  these  conidia  find  a  lodgment  on  the  surface 
of  media  which  are  slightly  acid  they  will  develop   and    begin   to 


40  BACTERIOLOGY  IN  CANNING. 

form  the  new  fungus  again,  but  should  they  be  submerged  below 
the  surface  of  any  fluid  so  that  the  supply  of  oxygen  from  the  air 
is  cut  off,  they  will  assume  a  different  character  entirely  from  the 
parent  fungus  and  resemble  the  saccharomyces  in  many  particu- 
lars, causing  feeble  alcoholic  fermentation  setting  free  large 
quantities  of  carbon  dioxide  and  multiply  by  sending  out  buds, 
which  is  so  characteristic  of  the  yeast  fungi.  It  has  often  been 
noticed  that  when  mold  forms  on  the  surface  of  preserves,  jellies  and 
other  food  products  that  it  does  not  cause  any  fermentation  of  those 
products  when  growth  is  luxuriant,  for  an  examination  will  disclose 
the  fact  that  the  products  are  perfectly  sweet  and  free  from  fer- 
mentation. Nor  can  any  other  ferment  get  a  hold,  unless  introduced 
below  the  surface.  The  reason  for  this  is  that  mold,  as  we  know  it 
and  see  it,  is  strongly  aerobic  organism,  requiring  vast  quantities 
of  oxygen  for  its  development.  When  once  started  to  grow  on  the 
surface  it  will  use  up  all  the  free  oxygen  it  requires,  and  any  other 
ferment  which  falls  from  the  air  on  the  surface  will  be  deprived 
of  the  oxygen  necessary  for  its  development,  and  will  lie  there 
merely  dormant.  Now,  when  the  conditions  are  changed,  the  sub- 
stance shaken  up  so  that  the  film  becomes  submerged,  thus  cutting 
off  its  natural  supply  of  oxygen,  it  will  obtain  whatever  oxygen  it 
requires  for  its  development  by  breaking  up  the  molecules  of  sugar. 
This,  no  doubt,  will  be  a  revelation  to  people  who  have  stored 
tomato  juice  in  barrels  for  making  tomato  catsup.  So  long  as  they 
remain  perfectly  quiet  in  the  cellar  they  would  appear  all  right, 
but  just  as  soon  as  they  were  rolled  over,  the  mold  flim  would  be- 
come submerged  and  fermentation  would  immediately  begin,  be- 
cause the  conidia  of  the  mold  would  be  deprived  of  the  oxygen  they 
were  obtaining  in  the  air  space  near  the  top  of  the  barrel,  and  would 
begin  to  feed  on  the  sugar  of  the  tomato  to  6btain  their  supply  of 
oxygen.  They  begin  budding  like  the  saccharomyces  and  in  a 
short  time  the  amount  of  carbon-dioxide  would  be  liberated  so  fast 
as  to  cause  the  barrel  to  burst. 

Pasteur  brought  to  light  a  peculiar  phenomenon  connected 
with  fermentation,  which  is,  that  if  the  yeast  germs  are  filtered  out 
of  a  fermenting  liquid,  that  there  remains  a  product  of  their  action, 
a  substance  insoluble  in  alcohol,  which  has  the  peculiar  power  to 
carry  on  the  fermentation  in  the  absence  of  the  germs  themselves ; 
that  this  substance  would  invert  saccharose  into  equal  parts  of 
dextrose  and  levulose,  and  this  substance  was  termed  invertine. 
This  invertine  will  convert  starch  into  sugar,  and  thus  produce  con- 
ditions favorable  to  the  cells  themselves.    Experiments  have  dem- 


BACTERIOLOGY  IN  CANNING.  41 

onstrated  that  the  cells  themselves  have  little  power  to  convert 
simple  sugar  water  into  its  elements.  There  must  be  something  else 
present,  and  we  find  that  nitrogen  is  necessary,  which  comes  from 
albuminoids.  In  other  words,  a  medium  must  be  made  nutrient 
before  it  can  be  fermented,  and  by  nutrient  I  mean  that  it  must 
contain  everything  necessary  for  the  development  of  the  organism. 

Special  forms  of  fermentation  is  due  to  the  peculiar  bacteria  of 
that  fermentation  and  the  nutrient  medium  must  contain  all  the  re- 
^quirements  of  those  bacteria.  I  can  demonstrate  more  fully  what 
I  mean  by  this  by  stating  that  a  given  bacterium  will  produce  or 
bring  about  certain  results  in  one  medium,  and  in  another  medium 
of  different  character  the  same  organisms  will  bring  about  different 
results.  A  quotation  from  Wood  conveys  the  idea  perfectly.  He 
says : 

"Of  still  greater  interest  is  the  varying  manner  in  which  the 
same  organism  conducts  itself  toward  different  albuminoids.  *  *  * 
As  a  general  rule,  those  organisms  which  liquefy  gelatine  are  able  to 
coagulate  milk,  and  then  peptonize  casein  which  has  been  separated ; 
but  some  organisms  which  peptonize  gelatine  are  without  action  on 
the  milk,  and  some  that  are  inoperative  on  gelatine,  peptonize  milk. 
''Very  striking  is  the  way  in  which  the  same  organism  conducts 
itself  towards  the  different  albuminoids,  gelatine,  fibrin,  blood 
serum  and  tgg  albumen ;  another  liquefies  the  gelatine,  but  cannot 
peptonize  the  egg  albumen.  *  *  *  They  must,  accordingly,  be  re- 
garded as  specific  in  their  nature,  depending  on  the  specific  nature 
of  the  protoplasm  of  which  they  are  merely  further  differentiations." 

The  product  of  micro-organisms  which  peptonizes  the  medium 
is  termed  an  enzyme.  When  gelatine  is  liquefied  or  when  meat  is 
softened  by  the  action  of  bacteria,  it  undergoes  the  same  charac- 
teristic changes  that  take  place  in  the  stomach,  and  we  term  this 
action  peptonization.  They  have  changed  from  coagulable  albu- 
mens to  soluble  albuminoids  and  in  this  state  are  easily  decomposed 
either  by  the  cell  protoplasm  or  the  animal  secretions.  This  pep- 
tonization is  accomplished  by  what  we  may  term  an  enzyme,  which 
is  the  product  of  bacterial  life,  especially  those  belonging  to  putre- 
faction. 

The  butyric  ferment  amylobacter  produces  an  enzyme  which 
accomplishes  the  butyric  fermentation  of  vegetable  and  fruit  acids^ 
the  ripening  of  cheese.  This  enzyme  acts  on  cellulose,  then  dex- 
trose and  glucose,  softens  the  fibre  and  solid  portions  of  any  sub- 
stratum peculiar  to  the  action  of  the  bacillus  and  prepares  the  way 
for  the  production  of  butyric  acid  by  the  bacillus.     When  this  bacil- 


42  BACTERIOLOGY  IN  CANNING. 

lus  begins  action  on  milk  it  first  coagulates  the  casein  which  is  lique- 
fied and  softened  by  the  enzyme  and  the  bacillus  is  then  able  to  pro- 
ceed on  the  softened  casein,  converting  it  into  lower  compounds 
such  as  leucine,  tyrosine  and  ammonia,  which  compounds  are  found 
also  in  the  ripening  process  of  cheese.  There  is  another  bacillus 
called  subtilis,  which  forms  an  enzyme  when  acting  on  the  casein 
of  milk,  coagulates  and  liquefies  it,  forming  leucine,  tyrosine,  car- 
bonic acid  gas,  ammonia  and  other  putrefactive  products,  and  the 
bacillus  takes  up  the  action  on  these  compounds  and  reduces  them 
to  still  lower  compounds. 

Nearly  all  putrefactive  organisms  have  this  power  of  produc- 
ing enzymes,  and  this  fact  led  many  observers  in  the  past  to  view 
the  process  of  fermentation  and  putrefaction  as  merely  chemical 
actions  and  in  no  way  attributable  to  cell  life. 

In  the  putrid  fermentation,  one  of  the  most  common  forms  of 
bacteria  found  is  the  butyric  ferment,  where  butyric  acid  is  formed 
and  other  organisms  produce  fatty  acids,  converting  starch,  lactic 
acid,  glucose  and  albuminous  substances,  and  also  fruit  juices  into 
fatty  acids,  carbonic  acid  g^s.  Lactic  acid  is  fermented  and  con- 
verted into  butyric  acid  with  carbonic  acid  gas  and  hydrogen. 

One  of  the  most  important  processes  of  fermentation  is  that  in 
which  lactic  acid  is  formed  by  the  bacillus  acidi  lactici  where  the 
sugar  of  the  milk  is  split  up  into  lactic  acid  without  the  production 
of  carbonic  acid  gas,  and  so  far  as  we  have  studied  the  subject,  this 
is  the  only  fermentation  which  takes  place  where  no  gas  is  formed. 
Owing  to  the  resisting  power  of  this  germ  against  high  temperature, 
it  is  a  very  dangerous  enemy  in  canning  where  milk  is  used  in  any 
product.  This  organism,  which  is  not  motile,  produces  wonderful 
changes  in  the  milk  after  all  other  organisms  have  been  killed  ofif 
by  the  ordinary  sterilizing  process,  when  it  is  left  in  a  pure  cultiva- 
tion to  act  on  the  milk  sugar.  This  sugar  is  split  up  into  lactic 
acid,  and  no  sign  is  visible  to  disclose  its  action.  The  formula  is 
simple,  one  molecule  of  milk  sugar  CgHj^Og  is  split  into  two 
molecules  of  lactic  acid  20311^03,  dividing  the  atoms  into 
equal  numbers,  and  no  discovery  of  this  change  can  be  noticed  until 
the  can  is  opened.  Under  no  circumstances  can  the  trouble  be 
ascertained  except  by  opening  the  cans.  Gradual  heating  will  not 
induce  any  gases  to  form  and  swell  the  cans,  because  the  action  is 
completed.  I  regard  this  form  of  fermentation  as  one  of  the  most 
peculiar  processes  ever  discovered,  and  one  which  is  all-important 
to  the  canner  who  uses  milk  in  any  product  which  he  prepares. 

If,  however,  there  should  be  any  butyric  ferments  present,  they 


BACTERIOLOGY  IN  CANNING.  43 

would  set  up  a  fermentation  of  the  lactic  acid  and  convert  it  into 
butyric  acid,  carbonic  acid  gas  and  hydrogen,  and  the  swelling  of  the 
cans  will  result  from  the  formation  of  the  gases  so  formed.  The 
chemical  formula  will  show  this 

2C.H,0.  =  C,H30,  +  2CO,  +  2H,. 

lactic  acid  butyric  acid         carbon        hydrogen 

dioxide 

These  formulae  will  give  an  idea  of  the  chemical  action  which 
takes  place  through  the  agency  of  these  minute  forms  of  bacterial 
life,  which  are  present  everywhere  in  the  atmosphere  in  the  seed 
form  or  spores.  As  we  have  observed  before  in  all  known  cases, 
excepting  that  of  the  peculiar  lactic  fermentation,  the  decomposing 
processes  are  performed  by  hydration,  which  is  the  formation  of 
gases,  such  as  carbon  dioxide,  hydrogen,  sulphuretted  hydrogen 
and  nitrogen.  Generally  the  aerobic  bacteria,  by  their  requirements 
of  free  oxygen,  cause  the  oxidation  of  the  products  of  decomposi- 
tion where  nascent  hydrogen  combines  with  oxygen  forming  water 
H,0. 

The  anaerobic  forms  deprived  of  free  oxygen  are  dependent 
upon  oxygen  in  combination  for  their  oxidation  of  lower  forms  of  de- 
composing elements.  Their  products  are  different  from  the  aerobic 
forms,  which  is  demonstrated  by  the  fact  that  the  gases  set  free  con- 
tain less  oxygen,  because  the  oxygen  which  they  obtain  from  the 
decomposing  matter  go  to  form  their  products,  such  as  leucine, 
tyrosine,  volatile  fatty  acids,  ammonia,  etc. 

From  the  study  of  the  statements  made  with  reference  to  fer- 
mentation in  previous  pages,  we  draw  conclusions  thus,  that  the 
process  of  reducing  a  fermentable  substance  to  elementary  forms  is 
not  that  of  any  single  form  of  bacterium,  but  is  the  result  of  con- 
tinual fermentation,  beginning  with  the  higher  bacterial  forms, 
which  produce  products  which  are  then  seizfed  upon  by  lower  forms 
which  form  more  simple  products,  which  in  their  turn  are  attacked 
by  still  lower  forms  until  action  entirely  ceases  or  until  such  simple 
products  are  set  free  as  elements  which  go  to  nourish  the  higher 
forms  of  animal  and  vegetable  life. 

It  is  interesting  to  note  the  influence  of  fermentation  on  plant 
life.  The  fermentation  of  dead  organic  matter,  which  covers  the 
ground  to  a  greater  or  less  extent,  is  carried  on  by  the  aerobic 
bacterial  forms,  and  oxidation  takes  place,  which  reduces  the  matter 
to  lower  forms,  and  the  surface  of  the  earth,  being  porous,  the  de- 
composition is  carried  downwards  along  with  the  spores  of  the 


44  BACTERIOLOGY  IN  CANNING. 

anaerobic  bacteria,  which  begin  at  once  to  act  on  this  matter,  and 
being  deprived  of  free  oxygen,  they  break  up  the  molecular  struc- 
ture of  the  matter  to  obtain  whatever  oxygen  they  need  for  their  de- 
velopment, and  products  thus  formed  are  no  longer  fit  for  bacterial 
action,  but  are  just  the  necessary  product  for  the  nutrition  of  higher 
plant  life.  This  fermentation  is,  of  course,  going  on  in  a  greater 
degree  where  the  fermentable  organic  matter  is  found  in  large  quan- 
tities. On  manured  ground,  in  the  gardens  and  on  the  farms,  this 
process  is  going  on,  and  the  action  of  micro-organisms  is  very 
necessary  for  the  growth  of  the  plants.  If  it  were  not  for  this  pro- 
cess of  fermentation  and  oxidation,  plant  life  would  be  deprived  of 
the  elements  of  nutrition  so  necessary  for  their  growth.  This  is  the 
reason  then  that  it  is  necessary  for  the  farmer  to  place  organic  mat- 
ter on  his  ground,  not  to  give  it  any  particular  color,  but  to  furnish 
iood  for  the  bacterial  forms  which  set  up  the  fermentation  so  neces- 
sary to  produce  the  elements  of  nutrition  for  his  growing  crop. 
Any  ground  which  is  cultivated  and  the  products  carried  away  with- 
out replacing  with  some  kind  of  fertilizer,  soon  becomes  barren.  The 
farmer  frequently  sows  his  ground  in  clover  or  grass  and  then  plows 
it  under  and  the  fermentation  of  this  cultivation  soon  takes  place, 
and  the  ground  is  thus  prepared  for  a  cultivation  of  his  salable 
crops.  Sometimes  there  is  an  excess  of  fermentation  which  is 
brought  about  by  fertilizing  with  a  fermentable  substance  which 
produces  too  much  heat  for  the  proper  growth  of  vegetation.  This 
is  the  case  where  fresh  manure  of  certain  kinds  is  used ;  the  fermen- 
tation is  entirely  too  violent  and  the  amount  of  heat  generated  by 
the  oxidation  is  too  great  for  the  plant,  and  it  often  falls  a  victim  to 
the  bacterial  life  itself. 

Manures  and  fertilizers  which  have  undergone  their  first  oxida- 
tion before  spreading  always  bring  the  best  results.  There  is  a  cer- 
tain amount  of  heat  set  free  by  the  final  processes  of  its  decomposi- 
tion, but  not  enough  to*endanger  the  plant.  This  moderate  supply 
of  heat  is  very  beneficial  to  the  seed,  which  will  soon  sprout  under 
its  influence. 

We  must  not,  however,  overlook  some  of  the  dangers  which 
result  from  the  manuring  of  ground,  especially  where  the  excreta 
comes  from  sources  of  infectious  disease.  Manure  from  stables  is 
not  dangerous,  generally  speaking,  except  that  the  growing  plants 
will  take  up  a  great  deal  more  nitrogenous  matter  from  such  soil. 
We  often  see  "com  come  into  the  canning  houses  with  beautifully 
formed  and  full  ears,  and  the  grains  are  large  and  full  of  milk ;  and 
that  very  corn  sometimes  causes  the  canner  a  great  deal  of  trouble, 


BACTERIOLOGY  IN  CANNING.  45. 

because  the  ears  are  covered  with  bacterial  forms  which  have  been 
decomposing  the  manures  in  the  field,  and  have  been  dried  up  by 
the  sun  and  wafted  by  the  winds  until  they  found  a  lodgment  on 
the  product,  only  waiting  for  the  right  time  to  come  for  the  proper 
conditions  to  begin  their  work  of  destruction.  Some  of  these  bac- 
terial forms  are  associated  with  the  class  of  putrefactive  ferments 
which  are  spore-bearing,  and  very  high  temperatures  are  required 
to  kill  them  in  the  sterilizing  processes. 

The  excreta  of  diseased  animals  are  very  dangerous  fertilizers, 
and  there  are  instances  of  infectious  diseases  transmitted  in  this 
way.  Especially  is  this  true  where  small  garden  truck  is  raised, 
which  is  eaten  in  its  green  state,  the  bacterial  forms,  disease  germs, 
which  are  flourishing  in  these  excreta,  find  their  way  to  the  leaves 
and  edible  portions,  and  when  eaten  sometimes  cause  infectious 
diseases. 

It  is  the  custom  in  China  to  save  all  human  excreta,  and  it  is 
also  true  in  some  localities  in  this  country,  where  it  is  hauled  out  of 
the  cities  and  dumped  on  neighboring  farms.  In  China  during  the 
ravages  of  cholera  epidemics,  scientists  made  microscopical  exam- 
inations of  garden  truck  sold  in  the  market  places,  and  found  on  let- 
tuce, kale  and  radishes  the  germs  of  cholera,  which  come  from 
the  excreta  of  people .  who  were  suffering  with  cholera.  All 
these  facts  as  stated  have  a  bearing  directly  on  the  canning 
and  preserving  industries,  and  summing  up  what  we  have 
learned,  we  would  suggest  that  the  canner  recommend  to  his 
growers  special  kinds  of  fertilizer,  which  would  be  free  to  a 
greater  or  less  extent  from  the  spores  of  putrefactive  ferments, 
as  they  are  so  hard  to  kill  in  the  sterilizing  process.  Of  course  the 
danger  from  ptomaines,  where  certain  kinds  of  excreta  are  used,  is 
possible  where  the  product  is  of  an  albuminous  nature,  but  we 
should  say  that,  generally  speaking,  ptomaine  poisoning  from  this 
source  is  not  so  common  in  canned  vegetables  as  it  is  in  the  canning 
of  meats  and  fish.  We  must  not  overlook  the  fact,  however,  that 
these  dangers  are  possible,  especially  where  the  poisonous  acid 
formed  from  tetanus,  which  is  so  common  in  manure,  may  find  its 
way  into  the  canning  product. 

We  cannot  fitly  close  this  subject  of  fermentation,  especially 
that  which  takes  place  upon  and  within  the  spongy  surface  of  the 
ground,  without  calling  atention  to  the  effect  of  all  this  upon  water. 
Since  such  large  quantities  of  water  are  used  in  these  industries,  it  is 
evident  to  the  mind  of  any  one,  after  studying  the  nature  of  fermen- 
tation and  the  organisms  which  cause  it,  that  the  water  used  should 


4J&  BACTERIOLOGY  IN  CANNING. 

be  as  pure  and  free  from  bacterial  life  as  possible.  Many  canning 
houses  get  their  supply  of  water  from  wells  by  pumping  it  up  to 
tanks,  from  which  it  is  used  to  make  the  various  sauces,  brines 
and  syrups  which  go  to  fill  up  the  can.  When  great  quantities  of 
organic  matter  are  decomposing  on  the  surface  of  the  ground, 
bacteria  are  carried  down  into  the  soil  and  frequently  find  their  way 
into  wells  and  cisterns.  This  water  is  termed  surface  water,  and 
should  not  be  used  where  it  comes  from  only  a  depth  of  15  or  20 
feet.  Water  is  a  great  medium  for  bacteria,  and  they  are  found  in 
great  numbers  in  surface  wells  where  there  is  seepage,  carrying  with 
it  decomposing  organic  matter.  We  find  in  deep  wells  very  few  or 
no  bacteria,  and  we  would  recommend  the  use  of  water  only  from 
such  wells.  If,  however,  this  is  found  to  be  impossible  and  only 
shallow  wells  are  available,  the  surface  of  the  ground  should  be  kept 
as  clean  as  possible  and  as  far  away  from  any  decomposing  matter 
as  is  practical.  There  is  a  tendency  on  the  part  of  canners  to  dump 
their  cobs,  when  packing  corn,  and  their  waste  of  every  character 
in  the  immediate  vicinity  of  the  factory.  This  should  be  avoided,  not 
only  for  fear  of  contaminating  the  water,  but  to  prevent  the  air  from 
being  laden  with  unusual  numbers  of  ferments. 

Fermentation,  then,  as  we  have  studied  it  in  these  pages,  is  a 
chemical  process,  in  one  form  accomplished  by  the  yeast  plant, 
which  converts  substances  of  a  nitrogenous  nature  which  contain 
sugar,  into  alcohol,  carbonic  acid  gas,  glycerine,  succinic  acid  and 
other  fatty  acids,  attended  with  heat,  and  accomplished  by  breaking 
up  the  molecules  of  sugar  to  obtain  the  oxygen  necessary  for  their 
reproduction  or  their  propagation,  when  the  supply  of  oxygen  is 
cut  off;  that  is,  the  free  oxygen  of  the  atmosphere.  In  the  pres- 
ence of  free  oxygen  the  yeast  plant  will  develop  more  rapidly,  but 
acts  less  as  a  ferment,  because  it  obtains  whatever  oxygen  it  needs 
for  its  development  from  the  atmosphere.  But  when  the  supply 
of  oxygen  is  cut  off,  the  molecular  construction  of  the  sugar  is  torn 
apart  and  the  oxygen  is  employed  to  make  the  chemical  change. 
We  have  seen  that  the  pencillium  and  all  other  mold  fungi, 
which  grow  naturally  on  the  surface  of  moist  acid  substances,  have 
the  same  characteristics  as  the  yeast  plant  when  submerged  or  im- 
bedded in  a  fermentable  substance,  which  cuts  off  the  supply  of 
oxygen  necessary  for  their  natural  development.  Under  these  con- 
ditions they  resemble  the  yeast  plant  very  closely,  both  in  appear- 
ance and  character.  The  process  of  fermentation  is  carried  on  after 
the  products  are  formed  by  the  higher  class  of  bacteria,  and  their 
products  are  attacked  and  decomposed  until  elementary  forms  are 


BACTERIOLOGY  IN  CANNING.  47 

obtained,  when  they  cease  to  exist.  So  we  have  fermentation  in 
which  alcohol  is  formed;  acidity,  in  which  acids  are  formed  from 
alcohol,  and  putrefaction,  in  which  acids  are  broken  up  into  more 
simple  acids  or  fatty  acids,  which  may  be  volatile.  A  molecule  re- 
solved into  simple  forms  is  the  great  scheme  of  nature  for  reducing 
accumulations  of  the  past  into  nutriment  for  the  future.  Thus  ani- 
mal and  vegetable  life  is  laid  low  and  the  elements  go  to  nourish  new 
Hfe. 

CHAPTER  VII. 

DIRECTIONS    FOR      STUDYING      BACTERIA.       METHODS    TO    OBTAIN 
PURE  CULTURES.      APPARATUS  TO   FACILITATE  THE  STUDY. 
INNOCULATION   OF  SOLID   CULTURE    MEDIA.      HOW  TO 
CULTIVATE  ANAEROBIC  ORGANISMS.      HANGING- 
DROP   CULTURES.      STAINING.* 

A  great  many  of  these  bacteria  are  useful,  others  are  causes  of 
disease  in  man  and  animals  and  still  others  attack  our  food  and 
make  it  unfit  for  consumption.  Bacteria,  by  which  we  mean  the 
whole  catalogue  of  monads  or  germs,  are  developed  either  from 
spores  or  dried-up  forms,  and  the  development  is  marked  by  an  in- 
crease of  protoplasm.  As  with  the  higher  forms  of  the  vegetable 
kingdom,  which  spring  from  seeds,  so  these  spores  and  dried-up 
forms  are  nothing  more  than  the  seeds.  These  seeds  are  held  in 
the  atmosphere  in  the  dust  or  clinging  to  any  floating  material.  So 
infinitely  small  are  they  that  the  microscope  fails  often  to  reveal 
them,  and  we  know  them  only  after  they  have  developed,  when  they 
may  be  viewed  and  studied  under  microscopic  power.  A  few  of 
the  following  pages  will  be  given  to  the  more  recent  methods  of 
studying  bacterial  life. 

A  steam  sterilizer  is  necessary,  with  which  we  can  sterilize  our 
culture  media.  The  ordinary  process  kettle  or  steam  retort  is  good, 
because  any  temperature  needed  can  be  obtained. 

An  incubator  is  necessary,  and  any  of  the  arrangements  for 
artificial  egg  hatching  are  all  right.  With  the  regulated  tempera- 
tures we  can  cultivate  our  bacteria. 

Test-tubes,  flasks,  cotton  wool,  pipettes  and  various  laboratory 
paraphernalia  are  all  useful. 

A  microscope  with  various  magnifying  appliances,  an  oil  im- 
mersion lens  of  1000  diameters  and  all  the  latest  accessories  to  a 
good  instrument.  Various  germicides  should  also  be  on  hand  for 
sterilizing  tubes,  flasks,  etc. ;  also  a  burner  to  sterilize  needles  and 
instruments  by  passing  them  through  the  flame. 


48  BACTERIOLOGY  IN  CANNING. 


FI,UID  CUI^TURE  M^DIA. 


Bouillon. — Cut  up  the  beef  in  small  strips,  and  put  them  into  an 
open  kettle,  covering  same  with  pure  cold  water.  Bring  this  to  a 
very  gentle  simmer  and  keep  it  so  for  six  or  eight  hours,  adding 
water  to  replace  evaporated  juice.  When  the  fluid  has  extracted 
all  the  juice,  draw  of?  from  the  bottom,  leaving  the  fat  in  the  kettle. 
The  bouillon  may  be  clarified  with  egg  albumen  or  blood.  After 
the  bouillon  is  clarified  it  may  be  rendered  slightly  alkaline  by  adding 
a  saturated  solution  of  mixed  sodium  hydrate,  sodium  carbonate 
or  sodium  phosphate.  The  bouillon  is  now  sterilized  by  boiling  same 
in  flasks,  test-tubes  or  cans,  discontinuously ;  that  is,  boiling  for 
twenty  minutes  for  three  successive  days,  allowing  same  to  stand 
in  a  cool  place  between  heatings,  but  the  flasks  and  tubes  must  be 
plugged  tightly  with  cotton  wool.  If  sealed  hermetically  in  a  tin 
can,  it  may  be  sterilized  by  giving  it  one  hour  at  250°  F.  in  the  steam 
retort.  The  bouillon  may  be  made  suitable  for  the  propagation  of 
various  organisms  by  the  addition  of  various  substances,  such  as  gly- 
cerine, salt,  albumen  peptone,  cane  or  grape  sugar,  acetic  acid,  man- 
nite,  etc.  Liebig's  extract  of  beef,  diluted  in  water,  is  also  an  excel- 
lent culture  medium,  and  must  be  sterilized  when  put  up  in  flasks, 
stoppered  with  cotton  wool,  by  Tyndall's  discontinuous  process,  by 
which  all  organisms  may  be  killed  at  low  temperatures.  After 
standing  in  a  cool  place  for  eight  or  ten  hours  the  second  heating 
will  kill  the  germs  which  have  developed  from  some  of  the  spores. 
More  spores  developing  in  the  next  period  are  killed  in  like  manner 
and  probably  all  will  succumb  in  another  heating.  Infusions  may 
also  be  made  from  fruits,  vegetables,  beer  wort,  etc.  Beer  wort  and 
prime  juice  is  an  excellent  medium  for  the  growth  of  mold  fungi 
and  mucors,  and  also  yeasts.  These  should  be  sterilized  by  either 
Tyndall's  discontinuous  method  or  by  sealing  in  cans  and  given  high 
temperatures  in  a  retort,  but  this  is  not  always  as  reliable  as  Tyn- 
dall's method. 

MII<K. 

Milk  is  a  very  favorable  culture  medium,  and  is  easily  obtained^ 
but  great  care  is  necessary  to  make  it  perfectly  sterile,  because  it 
is  so  easily  scorched  when  given  high  temperatures,  and  in  the  dis- 
continuous process  it  often  requires  an  hour's  boiling  at  each  time 
for  three  days. 

SOWD  CUI^TURB  MEDIA.       POTATO  CUI,TURB  MEDIUM. 

Cut  the  potato  in  strips  and  steam.  After  cooling  with  a  ster- 
ilized apple  corer,  cut  out  cylinders  and  cut  ofif  each  end,  and  insert 


BACTERIOLOGY  IN  CANNING.  49 

the  cylinder  into  a  test  tube  where  a  small  quantity  of  cotton  wool  is 
inserted  into  the  bottom  and  sterilized  by  dry  heat.  A  small  quan- 
tity of  distilled  water  is  then  let  into  the  tube  to  moisten  the  cotton 
wool  and  the  potato  will  rest  on  this  and  the  tube  will  be  closed  at 
the  top  with  a  plug  of  cotton  wool.  After  this  tube  is  boiled  for  a 
couple  of  hours  the  potato  is  ready  for  culture  of  bacteria. 

Another  zvay. — The  potato  may  be  pared  and  steamed,  cut  into 
small  pieces  and  filled  into  a  tin  can,  which  is  then  sealed.  Boil 
this  for  twenty  minutes,  then  tap  and  resolder.  Boil  this  again  for 
one  hour. 

BR^AD  CRUMBS. 

Evaporate  the  moisture  from  several  slices  of  bread  by  spread- 
ing them  in  an  oven  of  a  temperature  of  200*^  F.  Reduce  the  slices 
to  small  crumbs  and  cover  the  bottom  on  the  inside  of  the  flasks. 
Moisten  the  crumbs  with  distilled  water,  and  after  they  are  thor- 
oughly moist,  sterilize  same,  after  plugging  mouths  of  the  flasks  with 
cotton  wool,  by  discontinuous  heating  for  three  days.  By  adding 
various  fruit  juices  and  acids  this  makes  a  very  favorable  medium 
for  mold  fungi,  mucors  and  other  ingredients. 

EGG  AI^BUMEN. 

Eggs  are  also  used  for  cultures  of  micro-organisms.  After 
washing  the  shell  in  a  solution  of  bichloride  of  mercury,  a  small  chip 
is  carefully  removed  and  a  culture  of  a  specified  organism  is  in- 
serted through  the  skin,  which  is  then  closed  and  sealed  with  a  ster- 
ilized plaster.  The  culture  will  develop  and  its  action  studied  after 
the  development. 

KOCH'S  GEI,ATIN12ED  MEAT  PEPTONE    MEDIUM. 

To  prepare  Koch's  meat  jelly,  or  soHd  gelatine  medium,  cover 
a  small  piece  of  lean  beef  with  water  and  add  a  drop  or  two  of  muri- 
atic acid ;  allow  this  to  stand  in  a  cool  place  for  one  day,  after  which 
squeeze  through  a  cloth.  To  this  fluid  add  10  grams  of  albumen 
peptone,  5  grams  common  salt,  and  100  grams  of  pure  gelatine.  Mix 
in  a  flask  and  boil  for  half  an  hour  until  the  gelatine  is  thoroughly 
dissolved.  Render  this  liquid  slightly  alkaline  with  common  soda 
and  boil  again  for  an  hour ;  after  this  is  filtered  it  is  a  very  proper 
medium  for  the  propagation  of  pure  cultures  of  bacteria. 


50  BACTERIOLOGY  IN  CANNING. 

AGAR  PEPTONE  MEAT  JEI.I«Y. 

In  place  of  the  gelatine  in  the  above,  we  may  use  1.5  per 
cent.  agar.  This  is  prepared  in  the  same  manner  as  the  gelatine 
jelly,  except  that  it  requires  a  more  prolonged  boiling  before  it  can 
be  properly  filtered.  It  is  made  as  follows  :  Cut  into  small  pieces  15 
grams  of  agar,  place  in  a  porcelain  basin  and  soak  in  strong  brine 
for  one  day ;  remove  the  particles  of  dirt  and  wash  thoroughly,  after 
which  drain  off  the  water.  To  the  15  grams  of  agar  add  1000  grams 
of  water,  one  pound  of  beef,  10  grams  of  peptone,  5  grams  of  salt, 
or  1000  grams  of  water,  5  grams  Liebig's  extract  of  beef,  30  grams 
of  peptone  and  5  grains  saJt.  In  the  first  formula  the  beef  is  first 
extracted;  the  preparation  after  this  is  the  same  in  both  cases.  Be- 
fore transferring  fluid  gelatine  or  agar  meat  broth  or  other  fluid 
media  to  test  tubes  or  flasks,  these  should  be  perfectly  sterilized. 
With  a  sterilized  pipette  the  fluid  is  run  into  these  vessels,  the  plug 
is  returned  and  the  vessels  are  then  sterilized  for  ten  minutes  or  a 
quarter  of  an  hour  discontinuously  for  three  successive  days.  Ster- 
ilized paper  is  then  fastened  over  the  mouth. 

TO  INNOCUI^ATE  SOI,ID  CUI^TURE  MEDIA. 

Hold  the  test  tube  inverted  in  the  left  hand,  the  cotton  wool 
is  twisted  in  the  mouth  to  break  the  adhesion,  and  if  there  is  any 
dust  on  the  cotton  wool  it  must  be  first  singed.  The  plug  is  then 
removed,  great  care  being  taken  that  it  comes  not  in  contact  with 
any  source  of  infection.  The  platinum  or  glass  needle  with  its 
charge  of  seed  material  (by  this  I  mean  any  form  of  bacteria  desired 
to  be  cultivated)  is  then  plunged  straight  into  the  gelatinous  mass ; 
then  carefully  withdraw  and  replace  the  plug. 

TO  CUI,TIVATE  ANAEROBIC  ORGANISMS. 

A  simple  method  of  cultivating  anaerobic  bacteria  is  that  de- 
scribed by  Fraengel,  who  uses  a  test  tube  with  a  long  and  a  short 
glass  tube  passing  through  an  india  rubber  cork.  This,  after  being 
carefully  sterilized,  has  about  a  cubic  inch  of  nutrient  gelatine 
poured  into  it.  The  inoculation  is  made  and  the  india  rubber 
cork  with  its  two  tubes  is  pushed  home  into  the  mouth  of  the  test 
tube,  after  sterilizing  is  sealed.  A  stream  of  hydrogen  is  passed 
through  the  liquefied  gelatine  for  four  or  five  minutes  and  the  tube 
sealed  in  a  flame.  Another  very  good  method  is  to  boil  a  quantity 
of  agar  in  a  test  tube,  then  cool  as  quickly  as  possible  in  cold  water. 


BACTERIOI.QGY  IN  CANNING.  51 

It  is  then  inoculated  with  anaerobic  organisms,  a  layer  of  melted 
gelatine  is  poured  over  the  surface,  and  when  this  is  cool  a  drop  of 
bacillus  subtilis  is  run  on  the  surface  from  a  pipette.  As  the  bacillus 
subtilis  develops  and  grows,  it  uses  up  the  oxygen  at  the  surface  and 
the  organism  below  is  thus  placed  in  an  anaerobic  condition. 
Molds  have  the  same  characteristic,  as  the  subtilis  is  using  up  all  the 
oxygen  at  the  surface.  Anaerobic  bacteria  and  aerobic  bacteria  made 
to  grow  without  oxygen  can  be  cultivated  in  hermetically  sealed  tin 
cans.  This  is  a  far  simpler  method  of  cultivating  these  torms  and 
one  which  any  canner  can  easily  follow  himself  without  any  lessons 
in  fine  laboratory  work. 

HANGING  DROP   CUI^TURE. 

A  glass  slide  such  as  is  commonly  used  under  the  microscope  is 
obtained,  where  a  little  hollow  place  has  been  ground  out  and  pol- 
ished, so  that  a  cover  glass  laid  over  this  hollow  place  will  enclose 
quite  a  little  air  chamber.  If  a  tiny  drop  of  some  inoculated  fluid  be 
hung  on  the  under  side  of  the  cover  glass  within  this  air  chamber, 
and  the  cover  glass  is  then  sealed  fast  to  the  slide,  a  flat  surface  of 
the  hanging  drop  will  be  exposed  to  the  magnifying  lens  of  the 
microscope.  Here  the  bacteria  may  be  watched  and  studied  as  they 
develop,  and  this  is  one  of  the  most  beautiful  methods  of  examining 
their  character.  Micro-photographs  can  be  obtained,  and  those  we 
have  reproduced  in  this  work  were  made  from  this  hanging-drop 
culture. 

STAINING  BACTERIA. 

* 

On  account  of  the  transparent  nature  of  a  very  great  number  of 
bacteria,  it  is  necessary  to  resort  to  dyes,  in  order  to  be  able  to  see 
them.  Certain  forms  of  bacteria  look  very  much  alike  but  are  sus- 
ceptable  to  certain  kinds  of  dyes,  which  enables  the  observer  to 
distinguish  them. 

METHYLENE  BI^UE. 

This  color  is  kept  as  a  saturated  solution  of  alcohol.  Diluted 
in  water  it  gives  a  fine  blue  color  in  cover  glass  views.  After  drying 
the  object  and  passing  over  the  flame  of  a  lamp,  it  is  saturated  with 
a  diluted  methylene  color  for  a  few  minutes,  then  washed  in  water 
and  turned  on  edge  to  allow  the  water  to  flow  off.  It  becomes  dry 
again  and  is  mounted  in  xylol  balsam.  Kuhne's  methylene  blue  is 
made  as  follows,  and  is  a  good  stain  for  bacteriological  work :  Three 
g;Tams  of  methyl  blue,  dissolved  in  20  cubic   centimeters    alcohol 


52  BACTERIOLOGY  IN  CANNING. 

and  200  cc.  of  a  i-to-20  watery  solution  of  carbolic  acid.  Speci- 
mens left  in  this  solution  will  not  take  on  too  much  stain.  After 
washing  in  pure  water  and  afterward  with  a  weak  muriatic  acid 
water  the  specimens  will  assume  a  pale  blue.  They  are  then 
mounted  and  the  bacteria  will  be  plainly  seen.  Fuchsin  is  also 
used,  which  brings  out  the  organisms  plainly  to  view.  Other  dyes 
are  also  used,  viz :  iodine,  aniline,  eosine,  victoria  blue,  etc.,  et€. 

There  are  works  written  especially  on  staining,  and  any  one  de- 
siring to  take  up  the  subject  fully,  should  read  Kuhne's  work. 
m 

PURE  CUI.TURES. 

For  a  long  time  bacteria  were  claimed  for  the  animal  and  vege- 
taible  kingdoms,  but  after  pure  cultures  were  obtained  and  their 
manner  of  propagation  became  known,  they  were  classed  as  belong- 
to  the  vegetable  kingdom,  because  they  multiply  by  fission,  and  we 
find  the  peculiarities  of  the  vegetable  kingdom  are  characteristic  of 
bacteria,  viz :  the  sending  out  of  buds,  branching  and  lengthening,  * 
etc. 

On  account  of  the  poor  appliances  and  the  minuteness  of  the 
organisms,  together  with  the  fact  that  they  were  seldom  if  ever 
found  growing  alone,  the  question  of  obtaining  pure  cultures  became 
a  very  perplexing  problem.  Pasteur  obtained  almost  pure  cultures 
by  separation,  by  feeding  to  the  kind  of  organism  he  wished  to 
study  a  food  on  which  it  particularly  thrived  and  which  the  other 
other  organisms  failed  to  use  for  a  propagating  medium.  He  was 
thus  able  to  get  practically  pure  cultivations,  although  at  times  he 
failed  to  exclude  some  different  kinds  which  had  affinity  for  the 
product  he  was  using  as  a  medium,  but  their  growth  did  not  hinder 
him  from  obtaining  the  results  he  was  after. 

Klebs  adopted  a  fractional  method  to  obtain  pure  cultures. 
He  toolc  a  lively  growth  and  transferred  it  to  new  media,  and  by 
adding  different  kinds  of  juices  to  these  media  for  which  his  cultures 
had  special  affinity,  he  succeeded  in  obtaining  practically  pure  cul- 
tures. He  could  only  obtain  the  common  forms  by  this  method, 
however,  and  even  they  could  not  be  relied  upon  as  being  absolutely 
pure. 

Roberts  and  Cohn  obtained  pure  cultures  of  various  bacilli  by 
boiling  a  fermenting  fluid  so  as  to  kill  all  forms  excepting  the  more 
resistant.  They  obtained  by  this  method  quite  pure  cultures  of  vari- 
ous spore-bearing  bacilli,  among  which  was  the  bacillus  subtilis. 
This  method,  however,  had  a  very  limited  application. 

Lister  obtained  fairly  pure  cultivations  by  distribution.      He 


BACTERIOLOGY  IN  CANNING.  53; 

took  a  certain  growth  and  distributed  it  into  large  quantities  of  fluid, 
until  a  drop  would  contain  not  more  than  a  single  organism.  By- 
placing  a  single  drop  of  fluid  in  a  large  number  of  tubes  containing 
sterilized  media,  he  was  enabled  to  get  very  good  cultivations.  This 
method  was  very  laborious  and  complicated,  however,  especially 
when  working  with  organisms  which  were  difficult  to  grow,  such 
as  the  anaerobic  forms. 

It  is  to  Koch,  Klebs  and  Brefeld  that  we  owe  the  knowledge  of 
obtaining  pure  cultures  easily.  Koch  took  the  gelatine  method  and 
isolated  the  organisms  so  that  the  colonies  formed  could  be  trans- 
planted to  other  media  and  there  studied  in  their  purity.  After 
this  simple  method  was  discovered,  the  study  of  this  science  was 
taken  up  with  renewed  energy,  and  subjects  of  fermentation  and 
putrefaction  were  studied  more  carefully  and  definite  know^ledge  was 
obtained  which  began  to  clear  up  many  mysteries. 

CHAPTER  VIII. 

A   SUMMARY   OF    THE    CHARACTERISTICS    OF    VARIOUS    OKGANISMS 
FOUND   IN    FOOD   PRODUCTS.      BACILLUS   LACTICI   ACIDI.     BACIL- 
LUS    BUTYRICUS        BACILLUS     AMYLOBACTER.      BACILLUS 
PRODIGIOSUS.        BACILLUS       VISCOSUS.        BACILLUS 
FLUOR ESCENS    PUTIDUS. 
BACILLUS  ERYTHROSPORUS.    BACILLUS    CYANOGENUS.     BACILLUS  SUB^ 
TILIS       SACCHAROMYCEL    APICULATUS.    SACCHAROMYCES  EL- 
LIPSORDEUS.    SACCHAROMYES  CEkEVISIAE.    COMMA  B.\CIL- 
LUS.      KLEBS-LOEFFLFR   BACILLUS.      TYPHOID  BACIL- 
LUS.     TETANUS  BACILLUS.      BACILLUS 
LACTICI   ACIDI. 

DESCRIPTION.  Occurs  in    short,   stout    rods,    i     to 

1.7  /i*  in  length  and  .3  to  .4  /x  in  thickness  ;  usually  arranged  in 

*i/x  =  TTjkoofaninch. 
pairs,  sometimes,  though  not  often,  in  chains  of  four;  well-marked 
refractile  bodies,  which  are  regarded  as  spores,  which  are  usually 
placed  at  the  ends  of  the  rods. 

MOTILITY.  No  motion. 

TEMPERATURE.  From  lo^  C.  to  45°  C.  it  can  develop. 

CHARACTER.  Aerobic,  but  can  be  made  to  grow  anae- 

robic. 

GELATINE.  It  grows  on  gelatine  plates  as  small,  white 

points,  which  gradually  become  opaque  and  moist-looking,  forming 
a  thick  layer  of  from  one  to  tvM  millimeters  in  diameter.  Under 
the  microscope  these  colonies  appear  to  be  dark  yellow  in  the  mid- 
dle.    The  margins  are  irregularly  indented  and  toothed. 


«4  BACTERIOLOGY  IN  CANNING. 

IN  TUBES.  In  tubes  its  growth  appears  as  small  gran- 

ules along  the  line  of  puncture;  surface  growth  thick,  moist  and 
-opaque;  grows  very  slowly.  This  bacillus  was  found  by  Hueppe 
in  sour  milk. 

BACILI^US    BUTYRICUS 

DESCRIPTION.  Occurs    in    large,    thick    rods,    with 

&rounded  ends  of  from  3  to  10  fi  in  length  and  i  yLt  in  breadth  ; 
often  forms  chains.  This  bacillus  gives  rise  to  large,  well-defined 
spores,  which  are  very  resistant  to  heat. 

MOTILITY.  The  bacillus  is  very  motile. 

TEMPERATURE.  Grows  very  rapidly  at  a  temperature 

of  from  350  to4oO  C. 

CHARACTER.  This  is  a  iLrongly  anaerobic  organism. 

GELATINE.  Grows  on  plates  in  the  deep  layers  of  gela- 

tine as  a  delicate  yellow  mass,  which  assumes  a  brown  granular  ap- 
pearance later;  gelatine  is  rapidly  ]:quefied  and  runs  together. 

AGAR.  On  agar  the  bacilli  grow  as  viscid,  superficial 

yellow  layers. 

GELATINE  TUBES.  In  gelatine  tube  punctures,  cul- 

tures rapidly  cause  liquefaction  along  the  tracks  of  the  needle,  the 
fluid  becoming  cloudy.  The  superficial  is  grayish  white  or  yellow, 
forming  a  delicate  fetid  mass. 

FERMENTATIVE  CHARACTER.  This  is  one  of  the 

iforms  of  bacilli  giving  rise  to  butyric  fermentation,  and  is  found 
'in  milk  and  putrefying  vegetable  and  animal  matter.  Its  sheath 
:^plits  lengthwise  for  the  escape  of  the  spores. 

CI^OSTRIDIUM   BUTYRICUM   OR  BACILI.US  AMYI.OBACTER. 

The  character  of  this  organism  is  very  similar  to  the  one  de- 
ascribed  above,  but  gives  off  a  large  quantity  of  gas  which  has  the 
•odor  of  butyric  acid,  wlien  growing  on  a  solid  nutrient  medium. 

DESCRIPTION    OF    FUNCTIONS.  It    is    strongly 

anaerobic  and  transforms  sugar,  starch,  dextrine  and  the  lactates 
into  butyric  acid,  setting  free  carbonic  acid  gas  (CO  g)  and  hydrogen. 

Gelatine  is  liquefied  and  a  regular  fetid  scum  forms  on  the  sur- 
sface. 

TEMPERATURE.  Grows  rapidly  at  35^^  to  40°  C. 


BACTERIOLOGY  IN  CANNING.  55. 

BACII.I.US   PRODIGIOSUS. 

DESCRIPTION.  This  organism  occurs  as  egg-shaped 

cells  about  1  fi  in  diameter;  sometimes  it  is  rod-shaped,  or  may 
occur  in  the  form  of  threads.  Multiplies  by  division  with  marvelous 
rapidity.  One  of  the  smallest  forms  seen.  One  cubic  inch  could 
contain  1,000,000,000,000,000  (one  quadrillion). 

MOTILITY.  It  is  non-motile  as  a  rule;  under  certain 

conditions  has  a  peculiar  motion. 

TEMPERATURE.  Grows  rapidly  at  20°  to  22^  C. 

CHARACTER.  Aerobic — faaulative   anaerobic. 

GELATINE.  On  plates  it  grows  in  the  deep  layers  as^ 

gray  points ;  the  superficial  growths  form  small  gray  round  colonies- 
about  one  millimeter  in  diameter;  these  sink  into  the  gelatine, 
which  is  rapidly  liquefied,  but  remains  clear.  Viewed  with  ordinary 
low  powers  in  the  microscope,  the  deep  colonies  are  seen  to  be 
rounded  or  oval  and  have  sharp  outlines.  When  the  gelatine  is 
liquefied  a  beautiful  red  color  makes  its  appearance. 

AGAR.  On  agar,  in  the  deep  layers  it  grows  as  gray 

points.  On  the  surface,  where  there  is  free  oxygen  from  the  air  for- 
the  growing  cultivation,  a  beautiful  red  color  appears. 

POTATO.  A  beautiful  red  layer    is    formed,  which    is 

moist. 

BREAD.  Form  a  beautiful  red  patch,  which  has  given^ 

the  organism  the  name  of  bleeding  bread,  because  the  spot  so  much^ 
resembles  blood. 

ONION.  On  the  surface  of  chopped  onions  a  beautiful 

pink  color  is  given.  The  bacilli  themselves  are  colorless,  but  form: 
this  red  pigment  at  lower  temperatures.  It  has  the  odor  of  herrings 
brine  so  characteristic  of  putrefying  substances.  At  higher  tem- 
peratures it  loses  both  these  characteristics. 

MILK.  On  placing  a  culture  in  sterilized  milk,  the  milk- 

is  curdled  and  casein  is  precipitated. 

This  organism  has  the  power  of  turning  milk  sugar  and  saccha- 
rose into  lactic  acid  and  carbonic  acid  gas.  It  is  a  very  common 
form  and  occurs  in  almost  all  spontaneous  fermentation  and  putre- 
faction.    It  is  also  very  resistant  to  high  temperatures. 

BACITvI,US  VISCOSUS. 

DESCRIPTION.  Occurs  in  pairs  of  small  cocci  form- 

ing chains  and  zoogloea,  surrounded  by  an  envelope  of  slimy  or 
mucilaginous  matter.     The  cocci  measure  1.2  to  1.5  /^  in  diameter. 


56  BACTERIOLOGY  IN  CANNING. 

Under  certain  conditions  they  assume  rod  forms  from  2  to  3  /z  in 
length  and  i  /x  in  breadth.     Multiply  by  division. 

MOTILITY.  They  are  not  motile. 

TEMPERATURE.  At  20°  to  35^  C.  they  grow  rapidly. 

CHARACTER.  Aerobic,  faculative,  anaerobic. 

GELATINE.  On  plates  forms  gray  spots,  which  appear 

-cloudy  and  moist.    Gelatine  is  liquefied  and  gummy. 

POTATO.  They  grow  in  a  colorless,  moist  patch  over 

the  whole  surface.  No  envelope  is  visible  when  exposed  freely  to 
■the  atmosphere. 

BACII^IvUS  Ifl^UORESCENS  PUTIDUS. 

DESCRIPTION.  Short,    thin    bacillus,    with    rounded 

ends,  similar  to  the  bacillus  prodigiosus.  Green  pigment  bacillus. 
-Multiplies  by  division. 

jMOTILITY.  It  is  a  very  motile  organism. 

TEMPERATURE.  20°  to  35°  C. 

CHARACTER.  Aerobic,  faculative,  anaerobic. 

GELATINE.  In  the  deep  layers  of  gelatine  plates  forms 

•dark  colonies.  On  surface  appears  round  with  irregular  outline, 
giving  the  surrounding  gelatine  a  greenish  fluorescent  appearance. 

IN  TUBES.  In  tubes  there  is  cloudiness  along  the  track 

■of  the  needle  and  gelatine  is  colored  green. 

POTATO.  Grows  rapidly  on  potato,  forming  brown  and 

gray  colored  layers. 

MILK.  Gives  milk  the  green  color  so  often  seen. 

MEAT.  Forms  green  color  around  the  fatty  portions  and 

bone,  gradually  covering  the  whole  surface. 

ODOR.  The  odor  is  strongly  like  herring  brine  or  fish, 

and  very  offensive. 

It  is  resistant  to  high  temperatures,  and  is  a  common  organ- 
ism found  in  nearly  all  putrefying  matter. 

BACII.r.US  ERYTHROSPORUS. 

DESCRIPTION.  Occurs  as  slender  with  rounded  ends, 

single  or  in  threads,  which  contain  numbers  of  dull  red-colored 
spores,  which  may  l)e  distinctly  seen. 

GELATINE.  On  plates  forms  whitish   colonies  which 

spread  over  the  whole  surface,  giving  the  gelatine  a  fluorescent 
•appearance.  The  center  of  the  colonies  are  opaque  and  brownish, 
the  outer  edges  are  yellowish  green,  not  so  opaque,  and  a  radiate 
^marking  is  seen. 


BACTERIOLOGY  IN  CANNING.  57 

IN  TUBES.  Along  the  track  of  the  needle  and  at  the 

surface  the  growths  are  rapid,  and  the  gelatine  is  colored  a  yellow- 
ish green. 

POTATO.  On  potato  forms  reddish  brown  patches. 

This  is  an  organism  found  commonly  in  putrefying  matter  of 
albuminous  character  and  in  water. 

BACILIvUS  CYANOGENUS.      (BI.UE   MILK   BACILLUS.) 

DESCRIPTION.  Occurs  in  club-shaped  rods  from  i  to 

4  /A  in  length  by  .3  to  .5  /*  in  breadth.  Sometimes  when  spores  form 
in  the  middle  it  has  a  lemon  shape.  Spores  oftener  form  at  the  ends, 
giving  club  shape  to  it. 

MOTILITY.  It  is  an  exceedingly  motile  organism. 

TEMPERATURE.  At  15°  to  18^  C.  develops  color  rap- 

idly.   At  37°  C.  no  color  is  formed  at  all. 

GELATINE.  On  plates  forms  rounded,  whitish,  finely 

granular  colonies  with  smooth  outlines,  while  the  surrounding  gela- 
tine takes  on  a  light  green  or  greenish  brown  color. 

IN  TUBES.  In  gelatine  along  the  track  of  the  needle  it 

develops  with  a  club-shape  or  drumstick  appearance,  with  a  white 
spore-bearing  end  or  head.  The  surrounding  gelatine  becomes  a 
greenish  blue,  or  sometimes  very  dark  color. 

AGAR.  On  agar  it  presents  much  the  same  appearance, 

but  sometimes  the  growth  appears  gray  in  color.  The  green  color 
is  not  so  marked  as  in  a  gelatine  medium. 

POTATO.  It  forms  a  yellowish  layer  near  the  point  of 

inoculation,  while  the  surrounding  potato  is  coJored  green. 

BLOOD  SERUM.  No  color  is  imparted. 

MILK.  When    alkaline,    forms    a    slate    color.    When 

slightly  acid,  imparts  a  blue  color. 

This  is  a  very  common  putrefactive  organism,  and  occurs  in 
milk  more  frequently  than  anywhere  else.  It  can  withstand  the 
boiling  temperature  for  hours,  and  is  a  very  difficult  organism  to 
kill  in  spore  form. 

BACILLUS  SUBTILIS. 

DESCRIPTION.  Occurs  in  stout  rods  from  4  to  6  /i  in 

length  by  2  /x  in  breadth,  having  slightly  rounded  ends.  Bears 
large,  well-defined  spores  measuring  1.2  /a  in  length  by  6  /x  in 
breadth  when  the  supply  of  nutrition  is  gradually  cut  ofl.  Mul- 
tiplies by  sending  the  spore  from  a  break  in  the  cell  wall  across  the 
middle. 


58  BACTERIOLOGY  IN  CANNING. 

GELATINE.  Grows  on  plate  cultures  as  white,  rounded 

colonies  with  radiations ;  gelatine  is  rapidly  liquefied. 

IN  TUBES.  Along  the  track  of  the  needle  liquefies  the 

gelatine,  beginning  at  the  surface ;  occurs  first  as  small  white  colo- 
nies, which  have  a  yellowish  brown  color  with  hair-like  margin; 
outside  this  is  a  narrow  clear  zone,  and  beyond  this  is  a  grayish 
radiating  layer.     This  may  be  seen  with  a  low  power. 

AGAR.  Forms  a  dry,  wrinkled,  white  layer  of  creamy 

appearance. 

POTATO.  Grows  on  potato  in  moist  white  or  creamy 

layers,  which  afterwards  become  dry  and  granular. 

SERUM.  Liquefies  blood  serum. 

MOTILITY.  Is   a   very   motile   organism,    multiplying 

rapidly. 

TEMPERATURE.  Grows  best  at  30^  C. 

CHAllACTER.  Strongly  aerobic,  faculative,  anaerobic. 

The  bacilli  commonly  occur  in  infusions  of  hay  which  has  been 
boiled.  The  spores  are  very  resistant  to  heat,  in  fact,  they  are  the 
most  resistant  forms  to  high  temperatures  that  we  have  met. 

SACCHAROMYCES  APICUI^ATUS. 

DESCRIPTION.  Occurs   in   cultivation   fluids  of  fruit 

juices  as  lemon-shaped  cells.  Cells  sometimes  elongated,  crescent 
and  rod-shaped.  Multiplies  by  sending  out  two  kinds  of  buds,  one 
oval  and  the  other  lemon-shaped.     No  spore  formation  observed. 

IN  WIKE.  Sets  up  a  bottom  fermentation,  which  is  char- 

acteristic on  all  jui(fes  suitable  to  its  development,  producing  alco- 
hol feebly. 

ON  CANE  SUGAR.  Does  not  invert. 

ON  DEXTROSE.  Ferments  dextrose  feebly,  not  com- 

pletely. 

It  is  a  spontaneous  ferment  deposited  from  the  air  in  fruit 
juices.  Found  during  season  on  the  fruits.  In  winter  is  found  in 
the  soil  under  the  trees. 

SACCHAROMYCES  ELLIPSOIDEUS. 

DESCRIPTION.  Occurs   as   cells   usually  rounded   or 

ellipsoidal-shaped,  sometimes  in  sausage  form.  Bears  spores  with 
two  to  four  in  a  single  ascus,  which  measure  from  2  to  4  /i  in 
diameter.     Spores  develop  rapidly  at  25°  C.     Egg-shaped  spores. 

ON  BEER  WORT  GELATINE.  Colonies  on  surface 


BACTERIOLOGY  IN  CANNING.  59 

form  networK  along  the  line  of  the  inoculation  streak.  The  surface 
membrane  forms  rapidly  in  eight  to  twelve  days  at  33^  to  34°  C. 

IN  BEER  WORT.  Grows  as  a  low  ferment.     Produces 

alcohol. 

ON  TDMATO.  Multiplies  rapidly,  producing  cloudiness. 

ON  FRUIT  JUICES.  Produces  alcohol.     Fermentation 

and  film-formation  is  rapid.     Multiplies  by  budding. 

SACCHAROMYCES  CEREVISIAE. 

DESCRIPTION.  Cells   are   rounded  or  slightly   ellip- 

soidal, which  give  off  small  cells  or  buds.  Forms  in  a  film  in 
threads  which  grow  long  and  regular.  The  yeast  cells  form  nuclei. 
Forms  spores  well  defined  from  2.5  to  6  /x  in  diameter,  which  ara 
highly  refractile  and  easily  seen. 

TEMPERATURE.  Films  form  in  seven  to  ten  days  at 

2Qp  to  22*^  C.     Form  sausage-shaped  cells  at  6^  to  1 5°  C. 

ON  TOMATO  JUICE.  '  Spontaneous  fermentation,  pro- 

ducing alcohol  and  a  film  in  five  days. 

ON  FRUIT  JUICES.  Fermentation  rapid.    Multiplica- 

tion of  cells  very  fast.  Film  forms  in  eight  days.  Produces  alco- 
hol, gives  off  carbonic  acid  gas.  This  is  a  typical  English  high 
yeast. 

COMMA  BACII^LUS.       (CH0I,ERA. 

DESCRIPTION.  It   belongs    to   the   spirilla;    usually 

occurs  as  slightly  curved  rods  measuring  from  i  to  2  /a  in  length 
and  from  .5  to  .6  /x  in  thickness.  Instead  of  rods  may  be  grouped 
in  pairs;  forms  O's,  or  may  be  reversed,  forming  shapes  like  S; 
sometimes  forms  wavy  threads  of  10  to  30  bends. 

MOTILITY.  It  is  a  very  motile  organism. 

TEMPERATURE.  Thrives  best  at  blood-heat,  or  even 

higher. 

PLATE  CULTURE.  At  20°  C.  to  30^  C.  forms  light ' 

yellow  colonies,  having  irregular  outlines.  Liquefies  gelatine 
slightly  and  sinks  to  the  bottom,  leaving  a  clear  space. 

POTATO.  Grows  on  potato  as  a  brownish  film. 

PUNCTURE    GROWTH    IN    GELATINE.  Growth 

takes  place  along  the  whole  track  of  the  needle,  first  as  a  delicate 
white  cloud,  and  after  the  gelatine  is  liquefied  leaves  a  clear  zone 
around  the  streak.  The  surface  gelatine  is  liquefied  more  rapidly 
than  deeper  down. 


6o  BACTERIOLOGY  IN  CANNING. 

ON  AGAR.  On  surface  grow  as  pale,  translucent  streaks, 

and  below  the  streak  a  slight  opalescence  occurs,  which  is  charac- 
teristic.    Agar  is  not  liquefied. 

MEAT  BROTH.  Rapid  growth,  forming  grayish  pellicle 

on  surface. 

BLOOD  SERUM.  Rapid  growth.     Slight  liquefaction. 

MILK.  Milk  is  an  excellent  nutrient  medium  for  the 

organism,  which  grows  rapidly,  giving  an  aromatic,  sweetish  odor. 
Do  not  thrive  in  the  presence  of  acids  which  are  germicidal  to  them. 
The  organism  produces  ptomaine  poison.  Acting  on  albuminous 
substances  producing  poisonous  alkaloids. 

kleb's-loefft^ER  bacii.i,us  (diptheria.) 

DESCRIPTION.  Occurs     in     varying     length     rods, 

straight  or  slightly  bent,  3  to  6  /i,  with  one  or  both  ends  slightly 
swollen. 

MOTILITY.  It  is  a  very  motile  organism. 

CHARACTER.  Aerobic,  faculative,  anaerobic. 

TEMPERATURE.  Grows  rapidly  at  blood  heat.'    Can 

live  at  98°  C. 

GELATINE.        Does  not  grow  on  meat  peptone  gelatine. 

BLOOD  SERUM  SOLIDIFIED.  Grows  in  pure  cul- 

tures. 

AGAR.  Grows  at  35^  C.  but  soon  overrun  by  putrefactive 

organisms.  On  blood  serum  it  forms  colonies  visible  to  the  naked 
eye  in  one  day,  and  it  is  the  only  organism  known  to  do  that. 

Colonies  grow  as  small  rounded  grayish  points,  the  center  of 
which  are  more  opaque  than  the  periphery.  They  spread  rapidly, 
form  grayish  rounded  discs,  and  develop  long  before  any  colonies 
of  other  organisms  are  visible  to  the  eye. 

AGAR  PLATES.  Colonies  are  coarsely  granular,  dark 

brown,  rounded  or  oval.  Colonies  run  together,  making  irregular 
outlines. 

Superficial  colonies  are  lighter  in  color,  less  dense,  with  irregu- 
lar border. 

The  Klebs-Loeffler  bacillus  forms  ptomaines  and  toxines  which 
are  deadly  poisons,  resembling  snake  bite,  and  cause  muscular 
tremors,  convulsions  and  death.  It  is  easily  stained  by  Loeffler's 
alkaline  methylene  blue  or  by  Gram's  gentian  violet  method. 


BACTERIOLOGY  IN  CANNING.  6i 


TYPHOID  BACII.I.US. 


DESCKLPTION.  Occurs  in  short,  somewhat  thick  rods, 

about  2  to  3  /Lt  in  length  and  .3  to  .5  /i  in  thickness.  They  are 
rounded  at  the  ends.  In  pure  cultivations  grows  in  long  threads,, 
developing  flagella.     Multiplies  by  division. 

MOTILITY.  Wavy  motions  in  rods  and  threads  due  to 

flagella,  which  give  the  organism  a  snake-like  movement. 

TEMPERATURE.  Develops     rapidly    at    blood-heat. 

Aerobic  forms  are  resistant  to  heat. 

CHARACTER.  Either  aerobic  or  anaerobic. 

PLATE    CULTIVATIONS.  Develops    in    the    deeper 

layers  of  the  gelatine  as  small  white  points;  on  surface  as  moist 
gray  colonies  with  irregular  margins.  There  is  no  liquefaction 
around  the  growths. 

IN  TUBES.  Develops  rapidly  along  the  track  of  the 

needle.  Surface  cultures  resemble  mother  of  pearl  in  appearance; 
g^ows  over  the  entire  surface,  form  a  blue-gray  film,  also  same  color 
along  the  track  of  the  needle ;   outside  this  is  milky  in  appearance. 

POTATO.  Grows  on  surface;   invisible  except  by  moist 

appearance.  Thrives  exceptionally  well  where  the  nutrient  is 
slightly  acid. 

PRODUCTS.  Forms  an  acid  excretory  product,  which 

is  different  from  other  forms  which  produce  alkaloids.  This  acid 
has  been  named  typhotoxicon,  and  is  a  poisonous  product,  classed 
among  the  ptomaines. 

RESISTANT  POWER.  It  is  killed  at  100°  C.  in  ten 

minutes ;  14°  C.  is  too  cold  for  it  and  often  kills  it.     SunHght  and 

X-rays  kill  the  organism. 

I 

TETANUS  BACII.I,US. 

DESCRIPTION.  Bacillus  is  drumstick-shaped.   Occurs^ 

sometimes  a  long  thread,  which  breaks  up;  also  in  shorter  rods, 
which  develop  large,  well-defined  spores  at  the  ends. 

MOTILITY.  The  rods  are  motile. 

TEMPERATURE.  Spores    develop    at    blood-heat    in 

thirty  hours. 

CHARACTER.  Anaerobic. 

PURE  CULTURES.  Very  hard  to  obtain  on  account 

of  anaerobic  character.  Is  cultivated  in  an  atmosphere  of  hydro- 
gen. After  sowing  the  seed  in  gelatine  in  the  hydrogen  atmosphere,, 
it  developed  rapidly  along  with  other  drumstick-shaped  organisms 


€2  BACTERIOLOGY  IN  CANNING. 

and  give  rise  to  spores.  By  heating  them  to  80°  C.  all  other  forms 
were  killed,  also  the  tetanus  bacilli,  but  the  spores  were  not.  These 
spores  when  transplanted  again  into  another  nutrient  gelatine 
■developed  a  pure  cultivation. 

PRODUCTS.  From    pure    cultivations    their    products 

were  seen  to  be  a  basic  poison  or  ptomaine. 

Tetanin,  tetano-toxin  or  toxalbumen,  both  alkaloids,  are 
obtained. 

FOUND.  Dry  spores  develop  from  the  soil,  also  from  the 

cleanings  of  stables.     Found  wherever  there  are  horses. 

NATURE    OF    POISON    FORMED.  The  ptomaines 

formed  by  this  organism  produce  convulsions,  tremors,  lockjaw 
and  death.  Sometimes  gets  into  canned  meats,  fish,  etc.,  where 
anaerobic  conditions  are  favorable  to  its  development. 


CHAPTER  IX. 

SCIENTIFIC  PRINCIPLES  INVOLVED  IN  CANNING  AND    PRESERVING 
TEMPERATURES.       VACUUM.       ANAEROBIC     BACTERIA     AND 
THEIR  ACTION.      FORMS  GROWING  IN   AN  ANAEROBIC 
STATE.       SPRING  BOTTOMS     IN     CANNED     GOODS. 
CAUSES.     PRECAUTIONS.     CLEANLINESS.    DIS- 
POSAL OF  WASTE    MATERIAL.     SOLD- 
ERING SOLUTIONS. 

Wherever  it  is  possible  it  is  better  to  sterilize  any  goods  by 
using  higher  temperatures  than  boiling,  which  is  212°  F.,  unless 
the  discontinuous  process  is  used,  in  which  case  no  higher  tempera- 
ture is  needed.  The  discontinuous  process  at  the  boiling  tempera- 
ture could  not  be  used,  however,  if  it  was  necessary  to  cook  the 
product  very  much.  Meats  would  not  cook  tender  by  that  process, 
so  the  higher  temperature  would  be  better. 

By  using  high  temperatures,  the  time  of  cooking  is  shortened, 
and  the  sterilizing  effect  is  more  perfect.  Many  bacteria  which 
might  live  through  a  boiling  process  would  soon  perish  under  a 
high  temperature. 

The  following  list  of  products  and  the  necessary  temperatures, 
together  with  the  required  time,  will  be  valuable.  It  is  understood 
that  these  products  are  either  exhausted  or  hot  before  this  process 
is  begun : 


BACTERIOIvOGY  IN  CANNING. 


Corn                                      250° 

F 

55  minutes 

Young  Peas                         240° 

F 

15 

Marrowfats                            " 

25 

Milk                                        250° 

i-O       "       . 

Products  Containing  Milk  '* 

*yy      **       1 

Meats                                      •' 

55 

Meat  Soups                            " 

50 

Peaches                                240° 

no  time 

Cherries 

2 

Plums,  etc.                             " 

2        " 

Pears 

12        " 

Tomatoes                                " 

5        " 

Apples 

2        " 

Berries 

2        " 

Lima  Beans                            " 

1    *'. 

Pineapple                           .    ** 

if  liquid 


hot       cold  pack    10  minutes. 


ERRATA. 

Prnr.^r.r"'^  ''equired  in  processing  has  been  clmnged  after  goinff  to  pi-ess.    It  should  read- 

Tn  tt  ;T,;  liire  if  sT'if  !   ':  '""rr.   ''^'""^^^^  ^^^ "  ^^  minutes'cold  pacflTll'tes: 
in  ti.c  .i.»th  line  it  should  read  :  or  the  temperature  must  be  250   for  50  minutes. 

heat  themselves  of  course  require  a  longer  time  ana  a  nignci  Lcm- 
perature.  Fruits  and  tomatoes,  while  exposed  to  the  air  just  as 
much  as  other  products,  do  not  furnish  nutrition  for  many  of  the 
more  resistant  forms  of  bacteria,  and  their  acid  juices  act  in  many- 
instances  as  germicidal,  agents  against  them.  The  only  very  resist- 
ant forms  inimical  to  fruits  and  tomatoes  seem  to  be  the  molds, 
which  perish  at  212°  F.  in  a  moist  heat.  We  cannot  say  positively 
that  there  are  no  living  germs  within  a  can  simply  because  it  does 
not  swell.  There  may  be  many  which  do  not  perish  at  once  by  the 
sterilizing  Heat,  but  they  do  not  develop  because  the  substrata  are 
not  suitable  propagating  media  for  them,  consequently  they  are 
dormant.  In  the  case  of  milk  and  products  such  as  soup  which  con- 
tain milk,  however,  a  fermentation  may  take  place  without  the  cans 
swelling  by  the  agency  of  the  milk  bacilli,  which  break  up  the  sugar 
of  milk  into  lactic  acid  without  any  other  chemical  changes  and  the 
chemical  formula  will  be  shown  thus  Ce  Hi 2  Oe  =  2C3  He  O3, 
which  is,  one  molecule  of  sugar  equals  two  molecules  of  lactic  acid. 
In  order  to  steriHze  milk  either  the  discontinuous  process  must 
be  used  or  the  temperatures  must  be  250°  F.  for  JS  minutes. 

VACUUM. 

There  has  been  and  there  is  to-day  a  very  erroneous  belief  that 
the  perfect  keeping  qualities  of  goods  depend  upon  a  vacuum  being 
formed.  Some  packers  and  preservers  make  a  special  point  of  try- 
ing to  secure  this  vacuum  to  insure  the  keeping  qualities  of  their 
goods,  believing  that  if  the  supply  of  oxygen  is  cut  off  from  any  bac- 


€2  BACTERIOLOGY  IN  CANNING. 

and  give  rise  to  spores.  By  heating  them  to  80°  C.  all  other  forms 
were  killed,  also  the  tetanus  bacilli,  but  the  spores  were  not.  These 
spores  when  transplanted  again  into  another  nutrient  gelatine 
developed  a  pure  cultivation. 

PRODUCTS.  From    pure    cultivations    their   products 

were  seen  to  be  a  basic  poison  or  ptomaine. 

Tetanin,  tetano-toxin  or  toxalbumen,  both  alkaloids,  are 
obtained. 

FOUND.  Dry  spores  develop  from  the  soil,  also  from  the 

cleanings  of  stables.     Found  wherever  there  are  horses. 

NATURE    OF    POISON    FORMED.  The  ptomaines 

formed   by   this  organism   produce  convulsions,  tremors   lor-i^i— • 


SCIENTIFIC  PRINCIPLES  INVOLVED  IN  CANNING  AND    PRESERVING 
TEMPERATURES.       VACUUM.        ANAEROBIC     BACTERIA     AND 
THEIR  ACTION.      FORMS  GROWING   IN  AN  ANAEROBIC 
STATE.       SPRING  BOTTOMS     IN     CANNED     GOODS. 
CAUSES.     PRECAUTIONS.     CLEANLINESS.    DIS- 
POSAL OF  WASTE    MATERIAL.     SOLD- 
ERING SOLUTIONS. 

Wherever  it  is  possible  it  is  better  to  sterilize  any  goods  by 
using  higher  temperatures  than  boiling,  which  is  212°  F.,  unless 
the  discontinuous  process  is  used,  in  which  case  no  higher  tempera- 
ture is  needed.  The  discontinuous  process  at  the  boiling  tempera- 
ture could  not  be  used,  however,  if  it  was  necessary  to  cook  the 
product  very  much.  Meats  would  not  cook  tender  by  that  process, 
so  the  higher  temperature  would  be  better. 

By  using  high  temperatures,  the  time  of  cooking  is  shortened, 
and  the  sterilizing  effect  is  more  perfect.  Many  bacteria  which 
might  live  through  a  boiling  process  would  soon  perish  under  a 
high  temperature. 

The  following  list  of  products  and  the  necessary  temperatures, 
together  with  the  required  time,  will  be  valuable.  It  is  understood 
that  these  products  are  either  exhausted  or  hot  before  this  process 
is  begun : 


BACTERIOLOGY  IN  CANNING. 


'"Ra, 


Corn 

250° 

F    55  minutes 

Young  Peas 

240° 

F    15 

(( 

Marrowfats 

K 

25 

(( 

Milk 

250° 

io 

(( 

Products  Containing 

Milk  " 

^7 

"       i 

Meats 

'* 

55 

Meat  Soups 

(< 

50 

(( 

Peaches 

240° 

no  time 

Cherries 

" 

2 

<( 

Plums,  etc. 

(( 

2 

<< 

Pears 

<< 

12 

(( 

Tomatoes 

<( 

5 

(( 

Apples 

<t 

2 

(( 

Berries 

<( 

2 

(( 

Lima  Beans 

(( 

25 

(< 

Pineapple 

C( 

8 

i( 

Oysters,  No. 

I  cans 

l( 

10  to  12 

(< 

Oysters,  No. 

2  cans 

<( 

12  to  15 

(( 

if  liquid 


hot       cold  pack    10  minutes. 


The  differences  in  temperature  required  for  sterilizing  the  above 
are  due  to  their  nature.  Products  which  are  poor  conductors  of 
heat  themselves  of  course  require  a  longer  time  and  a  higher  tem- 
perature. Fruits  and  tomatoes,  while  exposed  to  the  air  just  as 
much  as  other  products,  do  not  furnish  nutrition  for  many  of  the 
more  resistant  forms  of  bacteria,  and  their  acid  juices  act  in  many 
instances  as  germicidal,  agents  against  them.  The  only  very  resist- 
ant forms  inimical  to  fruits  and  tomatoes  seem  to  be  the  molds, 
which  perish  at  212°  F.  in  a  moist  heat.  We  cannot  say  positively 
that  there  are  no  living  germs  within  a  can  simply  because  it  does 
not  swell.  There  may  be  many  which  do  not  perish  at  once  by  the 
sterilizing  Heat,  but  they  do  not  develop  because  the  substrata  are 
not  suitable  propagating  media  for  them,  consequently  they  are 
dormant.  In  the  case  of  milk  and  products  such  as  soup  which  con- 
tain milk,  however,  a  fermentation  may  take  place  without  the  cans 
swelling  by  the  agency  of  the  milk  bacilli,  which  break  up  the  sugar 
of  milk  into  lactic  acid  without  any  other  chemical  changes  and  the 
chemical  formula  will  be  shown  thus  Ce  Hi 2  Oe  =  2C3  He  O3, 
which  is,  one  molecule  of  sugar  equals  two  molecules  of  lactic  acid. 

In  order  to  steriHze  milk  either  the  discontinuous  process  must 
be  used  or  the  temperaturesf  must  be  250°  F.  for  Jo  minutes. 

VACUUM. 


There  has  been  and  there  is  to-day  a  very  erroneous  belief  that 
the  perfect  keeping  qualities  of  goods  depend  upon  a  vacuum  being 
formed.  Some  packers  and  preservers  make  a  special  point  of  try- 
ing to  secure  this  vacuum  to  insure  the  keeping  qualities  of  their 
goods,  believing  that  if  the  supply  of  oxygen  is  cut  off  from  any  bac- 


64  BACTERIOLOGY  IN  CANNING. 

teria  within  the  goods,  that  their  power  to  cause  fermentation  is  de- 
stroyed. For  this  reason  many  bottlers  of  condiments  exhaust 
their  bottles  and  use  a  very  large  cork,  which  they  compress  to  keep 
out  the  germs,  and  prevent  fermentation  of  those  within. 

The  only  benefit  a  vacuum  is  to  a  canner  is  its  power  to  draw 
back  the  ends  of  the  cans  which  are  bulged  out  in  the  cooking  pro- 
cess, for  all  other  purposes  it  is  a  detriment  instead  of  a  help  in  pre- 
venting fermentation. 

From  our  study  of  fermentation  we  learned  that  there  were  two 
kinds  of  micro-organisms  with  reference  to  life  with  or  without 
oxygen.  We  learned  that  there  were  some  organisms  which  could 
only  live  without  free  oxygen,  and  these  we  called  anaerobic. 

We  learned  that  there  were  others  which  needed  oxygen  for 
their  development  and  these  we  call  aerobic.  The  most  of  the 
aerobic  genns  grow  rapidly  in  the  presence  of  free  atmospheric 
oxygen,  but  act  less  as  ferments  when  thus  growing ;  they  act  most 
as  ferments  when  forced  into  an  anaerobic  condition  where  they  re- 
quire oxygen,  but  are  cut  off  from  their  natural  supply  from  the  air, 
so  in  order  to  obtain  what  they  need  for  their  development  they  seize 
the  oxygen  and  wrest  or  tear  it  away  from  those  molecules  which 
contain  it.  As  sugar  contains  a  large  per  cent,  and  is  itself  a  most 
excellent  medium  for  propagation  when  present  with  nitrogenous 
mater,  it  falls  a  prey  to  these  aerobic  germs  which  have  been  forced 
into  an  anaerobic  condition.  The  fermentation  in  this  case  is  much 
more  violent,  and  the  pressure  of  gas  formed  in  that  fermentation 
is  sometimes  very  great,  exceeding  50  pounds  to  the  square  inch. 

We  thus  see  that  packers  who  are  pinning  their  faith  to  a 
a  vacuum  are  depending  upon  a  broken  reed.  A  vacuum  has  no 
value  whatever  in  preventing  fermentation,  and  we  can  truthfully 
state  that  it  is  a  good  condition  for  fermentation, 

A  very  pretty  experiment  to  show  that  a  vacuum  is  not  a  neces- 
sity for  preserving  goods  can  be  made  by  puncturing  a  sterilized  can 
of  com.  By  holding  a  hot  flame  on  the  tin  and  punching  a  very 
small  hole  with  a  hot  punch  directly  through  the  flame,  the  vacuum 
will  draw  in  enough  air  to  fill  the  space ;  the  air  which  is  drawn  into 
the  can  will  be  pure,  as  all  the  spores  of  bacteria  which  are  in  that 
air  will  be  destroyed  by  the  flame.  The  can  must  then  be  sealed 
while  the  flame  is  still  on  the  spot,  and  the  can  will  keep  just  the 
same  as  if  it  still  possessed  a  vacuum.  This  proves  two  things: 
first,  that  the  vacuum  was  not  necessary  for  the  prevention  of  fer- 
mentation, and  second,  that  the  air  when  pure  and  free  from  live- 
spores  will  not  cause  fermentation.  By  puncturing  another  can  with- 


BACTERIOLOGY  IN  CANNING.  65 

out  the  flame  as  a  g^rm  destroyer,  it  will  be  demonstrated  that  germs 
thus  drawn  into  the  can  will  cause  fermentation  in  a  short  time.  If 
the  can  should  be  inoculated  with  spores  of  resistant  forms  of  bac- 
teria while  the  can  is  still  hot,  and  after  sealing  and  chilling,  a 
vacuum  will  form  at  once,  but  if  the  can  be  incubated  at  85*^  F.  it 
will  swell  in  a  short  time,  which  proves  that  the  spores  developed 
in  the  vacuum  and  that  the  fermentation  was  violent. 

If  a  can  of  cool  tomato  juice  be  left  open  for  a  few  hours  and 
another  can  of  the  same  juice  be  sealed  tight,  the  first  will  remain 
apparently  sweet  as  far  as  taste  and  smell  is  concerned,  while  the 
sealed  can  will  ferment  and  swell.  I  have  filled  tomato  juice  cold 
into  barrels  and  left  some  of  the  bungholes  open  overnight, 
while  others  I  have  bunged.  In  nearly  every  case  the  open  barrels 
would  remain  sweet  overnight,  while  those  barrels  which  were  bung- 
ed up  would  often  burst  before  morning  and  the  contents  would  be 
fermenting  most  violently.  In  the  first  case  those  germs  which 
found  a  lodgment  on  the  surface  of  the  juice  would  take  from  the 
air  the  oxygen  necessary  for  their  development ;  in  the  second  case, 
the  supply  from  the  air  was  cut  oflf,  so  the  sugar  was  broken  up  in 
order  to  supply  the  oxygen  demanded. 

A  PECUWAR  PHBNOMKNON,    "SPRING  BOTTMOS". 

In  the  springtime  it  happens  that  springs  will  often  develop 
in  cans  which  have  stood  all  fall  and  winter  in  vacuo.  Some- 
times these  cans  will  swell  and  ferment,  sometimes  the  fruits  will 
remain  perfectly  good.  Now  the  question  arises,  how  does  it  hap- 
pen that  after  so  long  a  time  this  phenomenon  occurs.  We  have 
seen  cans  of  tomatoes  opened  and  the  seeds  planted  and  they  grew 
and  the  vines  bore  tomatoes,  all  this  after  the  tomato  had  been  pro- 
cessed in  boiling  water. 

The  solution  of  this  phenomenon  is  interesting  from  the  fact 
that  some  scientific  principles  are  involved,  and  which,  when 
known,  will  obviate  the  trouble.  If  fruits  which  are  processed  in 
the  fall  and  in  the  cool  weather  be  not  perfectly  sterilized,  there  may 
remain  the  spores  of  some  varieties  of  bacteria  which  will  not  de- 
velop in  the  cold  weather,  but  when  the  warm  days  in  the  spring- 
time come,  the  temperatures  become  more  favorable  for  the  devel- 
opment of  the  dormant  spores,  and  fermentation  soon  sets  in, 
which  spoils  the  goods.  In  the  cases  where  springs  occur  without 
spoilage,  the  phenomenon  is  due  to  the  cell-life  of  the  fruit  itself, 
which  has  not  been  destroyed  in  the  process. 


66  BACTERIOLOGY  IN  CANNING. 

A  tomato,  a  peach,  a  pear,  a  plum,  or  any  fruit,  is  just  exactly 
the  same  in  nature  as  a  germ.  The  fruit  is  a  large  cell  with  living 
protoplasm  and  has  the  power  of  setting  up  alcoholic  fermentation 
just  the  same  as  the  saccharomyces,  only  far  more  feebly.  Fruits 
and  tomatoes  which  have  been  heated  only  enough  to  kill  the  bac- 
teria which  are  on  the  outside  and  in  the  liquid  portion,  have  not 
been  killed  themselves,  and  so  when  the  temperature  rises  in  the 
springtime  they  evolve  a  small  quantity  of  gas  and  set  up  a  feeble 
fermentation  from  their  own  vitality.  If  we  place  a  whole  tomato, 
which  has  been  washed  perfectly  clean,  in  a  nutrient  sugar  solution 
and  sterilize  only  enough  to  kill  any  bacteria  which  may  be  in  the 
fluid  or  on  the  outside  of  the  tomato,  and  then  incubate  the  can  at 
85^  F.,  the  sugar  will  ferment  slightly  and  an  appreciable  quantity  of 
alcohol  will  be  formed,  together  with  some  carbon  dioxide. 

After  removing  the  tomato  we  will  find  that  it  has  lost  some  of 
its  own  sugar  and  the  seeds  will  all  be  alive,  and  will  grow  if  planted 
again.  A  fermentation  of  this  kind  will  never  be  very  violent,  and  sel- 
dom goes  on  for  a  very  long  time,  because  the  conditions  for  the  de- 
velopment of  the  tomato  are  not  perfect.  If  the  medium  and  condi- 
tions were  favorable  for  new  tomato  plants  to  start,  we  have  no  doubt 
that  many  of  the  phenomena  peculiar  to  bacteria  might  be  observed 
in  this  large  vegetable  cell.  We  do  see  these  conditions  going  on 
in  the  ground,  but  never  in  a  pure  form,  as  the  fruits  fall  a  prey  to 
common  bacterial  life  at  once  and  only  the  seeds  are  left  to  sprout, 
while  the  surrounding  protoplasm  has  been  decomposed  by  bacteria. 
The  whole  fruit  then  must  be  called  a  cell,  with  the  seed  represent- 
ing the  spore  life,  and  the  surrounding  meat  is  the  living  proto- 
plasm, and  the  skin  may  be  likened  to  the  cell  wall  of  a  bacillus. 
Where  the  temperature  in  the  sterilizing  process  has  been  raised 
to  240^  F.  for  only  a  short  time,  this  cqll  life  is  generally  destroyed, 
and  it  should  be  in  order  to  prevent  springs. 

GENERAL  PRECAUTIONS   AND  CI^EANI^INESS. 

When  the  canning  products  are  brought  into  the  factory,  they 
should  be  placed  in  a  cool,  shady  place  if  possible,  or  at  least  where 
plenty  of  air  can  circulate  between  and  around  them.  Farm  pro- 
ducts should  never  be  placed  too  close  together.  If  corn  comes  in 
faster  than  it  can  be  handled,  it  should  be  spread  as  much  as  pos- 
sible, so  that  plenty  of  air  can  circulate  between  the  ears.  Toma- 
toes should  be  piled  in  boxes  with  sufficiently  large  openings 
between  the  slats.  Any  product  whatsoever  should  have  plenty  of 
air  circulation.     Of  course,  it  is  better  to  work  it  up  as  fast  as  it 


BACTERIOLOGY  IN  CANNING.  67 

comes  in,  and  the  capacity  should  be  increased  to  take  care  of  it 
at  all  times,  even  if  some  machinery  is  idle  part  of  the  time.  No 
goods  should  be  carried  overnight  to  give  a  start  in  the  morning. 
The  tendency  is  to  carry  too  much  overnight,  and  often  on  account 
of  limited  space  it  happens  that  proper  circulation  cannot  be  given, 
and  fermentation  and  mold  will  quickly  develop  when  the  nights  are 
hot.  It  is  far  better  to  compel  the  farmers  to  get  their  products  in 
early,  and  if  any  stock  is  to  be  carried  overnight,  let  them  do  it. 
Out  in  the  country  it  is  generally  cooler  than  in  the  factory,  and  the 
farmer  can  spread  his  product  and  deliver  early  in  the  morning. 
Meats,  fish,  etc.,  should  be  kept  in  a  freezing  temperature  at  all 
times  before  the  canning  process  begins. 

Speaking  of  fermentation  starting  wheil  products  are  not 
allowed  proper  circulation,  shows  us  again  clearly  one  of  the  great 
principles  in  bacteriology.  When  the  circulation  of  air  is  cut  off, 
the  product  is  in  an  aerobic  state  to  a  great  extent.  The  germs 
which  are  all  over  the  product,  being  cut  off  from  free  atmospheric 
oxygen,  will  wrest  the  oxygen  from  the  product  to  gain  develop- 
ment, and  the  energy  of  the  change  of  this  oxygen  from  one  set  of 
molecules  to  another  is  released  in  the  form  of  heat,  which  can  be 
seen  at  all  times  where  these  conditions  exist.  Probably  the  first 
germs  to  act  in  this  manner  are  the  molds.  The  little  plants  cause 
no  perceptible  fermentation  where  the  products  are  piled  for  only  a 
short  time  with  plenty  of  circulation,  but  when  the  air  is  cut  off  the 
little  bead-like  forms  called  conidia  will  start  the  fermentation  very 
quickly,  and  these  conidia  will  cause  a  great  deal  of  trouble  if  they 
get  a  good  start,  and  the  haste  required  to  save  the  product  and  the 
canned  goods  is  often  inadequate  to  prevent  souring  during  the 
canning  process. 

Another  fact  we  must  not  overlook  in  this  connection  is  that 
when  the  products  are  allowed  to  become  heated,  which  is  an  evi- 
dence of  fermentation,  the  natural  sugar  is  being  fast  converted  into 
acids,  and  of  course  the  quality  is  injured. 

It  will  Be  remembered  also  that  we  have  discovered  that  fruit 
and  vegetables  are  themselves  similar  in  characteristics  to  bacteria, 
although  not  so  strongly  capable  of  causing  fermentation. 

When  these  fruits  and  vegetables  are  piled  closely  together  they 
will  have  an  action  upon  one  another  similar  in  many  respects  to 
alcoholic  fermentation,  and  it  is  for  this  reason  that  our  California 
fruits  are  packed  in  sawdust  or  papers,  so  that  they  will  not  come 
in  contact  with  each  other.  With  some  fruits  this  action  is  very 
slow,  but  in  succulent  fruits  and  berries  the  danger  of  fermentation 
is  very  much  greater. 


68  BACTERIOLOGY  IN  CANNING. 

All  waste  material,  such  as  cobs,  peelings,  cores,  seeds,  etc., 
should  never  be  allowed  ^o  stand  near  the  factory  and  ferment, 
because  the  air  in  the  vicinity  will  fairly  teem  with  the  spores  of  the 
very  forms  most  inimical  to  product  which  is  being  canned.  We 
know  that  even  in  the  purest  air  the  numbers  of  the  various  ferments 
are  very  great,  but  we  can  realize  how  much  greater  in  numbers 
they  will  be  if  this  fermentation  goes  on  close  to  the  factory.  When- 
ever a  disagreeable  odor  is  present  near  a  canning  factory,  it  is  evi- 
dent that  putrefaction  is  going  on,  either  inside  or  close  by,  and  if 
the  odor  is  perceptible,  how  full  must  the  air  be  of  these  bacteria. 
The  air  ordinarily  contains  great  numbers  of  the  common  ferments 
peculiar  to  every  kind  of  product,  but  it  is  evident  that  the  fewer 
forms  there  are  present  the  less  risk  is  taken  in  the  canning  of  those 
products. 

Mold  is  one  of  the  most  common  forms  to  be  seen  around 
canning  houses,  and  it  is  hard  to  keep  out,  too.  It  will  be  seen 
growing  on  the  floors  and  walls,  on  the  tables  and  wooden  portions 
of  maciiinery,  and  when  we  think  of  the  myriads  of  the  little  conidia, 
resembling  dust,  which  are  blown  hither  and  thither  by  every 
draught  of  air,  we  cannot  overestimate  the  value  of  precautions 
against  them. 

Whitewash  is  a  good  purifier,  and  should  be  liberally  used,  and 
at  night  it  might  be  good  policy  to  let  some  one  close  up  the  rooms- 
and  burn  sulphur,  the  fumes  of  which  combine  with  the  oxygen  in 
the  air,  which  is  so  necessary  for  the  growth  of  the  fungus,  and  the 
result  will  cause  it  to  die.  In  this  manner,  by  constant  care,  a  can- 
ning factory  may  be  kept  in  very  good  condition. 

We  cannot  overestimate  the  value  of  absolute  cleanliness 
throughout  the  factory,  and  the  carelessness  so  prevalent  in  many 
quarters  along  this  line  has  brought  a  great  deal  of  discredit  on  the 
business.  It  is  a  very  common  remark  so  often  heard,  "I  would 
not  eat  any  canned  goods,  because  I  have  seen  how  filthy  those 
canning  factories  are."  Any  packer  who  gives  a  visitor  such  an 
impression  has  done  more  to  injure  his  business  than  a  whole  batch 
of  sour  goods. 

It  sometimes  takes  a  wise  man  to  see  a  twenty-dollar  gold  piece 
behind  a  nickel,  but  do  you  know  that  success  is  built  upon  far- 
sightedness? Any  man  who  is  far-sighted  enough  to  spend  his 
money  on  soap  and  scrubbing  brushes  and  labor  to  keep  his  place 
scrupulously  clean,  and  advertise  the  fact,  and  invite  people  to  visit 
and  see  it,  will  in  the  long  run  be  the  gainer  by  a  large  per  cent. 

From  a  bacteriological  standpoint,  cleanliness  is  a  great  factor 


BACTERIOLOGY  IN  CANNING.  69 

in  preventing  loss.  Filth  is  decomposing  matter  full  of  bacteria, 
which,  like  the  mold,  is  a  menace  to  the  goods  in  the  process  of 
canning,  and  certain  time  should  be  given  each  day  for  the  removal 
of  all  that  goes  to  make  a  place  filthy  and  untidy.  Not  only  should 
these  precautions  be  taken  in  the  factory  itself,  but  all  the  people 
who  are  employed  should  be  compelled  to  keep  themselves  clean 
and  tidy.  Such  a  place  is  a  credit  to  the  business,  and  if  I  could 
get  every  man  to  follow  out  these  principles,  the  days  of  home  can- 
ning and  preserving  would  decrease  very  rapidly.  Give  the  people 
the  proof  that  your  goods  are  clean  and  they  will  eat  them. 

"  Cleanliness  is  next  to  Godliness  "  is  an  old  adage,  and  you 
will  find  that  care  along  this  line  will  have  a  moral  influence  on  all 
your  help ;  the  managers  will  be  more  on  the  alert,  more  watchful, 
and  likewise  the  employees  will  be  more  careful  even  in  their  work, 
and  the  result  will  be  that  you  will  have  less  waste  and  less  spoilage. 

SOI^DERING  SOI.UTIONS. 

Almost  all  fluxes  used  in  soldering  have  more  or  less  chloride 
of  zinc  present,  which  is  the  best  for  general  purposes,  but  care 
should  be  exercised  in  its  use,  because  a  small  quantity  allowed  to 
get  into  the  goods  injures  the  quality  and  is  poisonous  to  those  who 
eat  the  goods.  Mechanical  arrangements  are  necessary  to  supply 
this  in  such  a  way  as  to  prevent  its  getting  inside  the  cans.  It  is 
quite  easily  detected  and  deposited  by  sulphuretted  hydrogen,  and 
each  canner  should  have  his  goods  examined  occasionally  to  be 
sure  that  his  goods  are  free.  Oils  of  various  kinds  are  used,  and 
some  patented  solutions,  but  the  most  of  these  will  show  at  least  35 
per  cent,  chloride  of  zinc. 

CHAPTER  X. 

.      ANTISEPTICS  AND  GERMICIDES.      VARIOUS  CHMEICA^S  USED 

AS  SUCH. 

The  use  of  antiseptics  is  not  to  be  recommended  in  the  canning 
and  preserving  industries.  There  is  absolutely  no  excuse  for  their 
use  in  canned  goods  at  all,  and  only  a  very  lame  excuse  for  their 
use  in  other  products,  but  as  stated  before,  where  the  product  might 
cause  more  damage  to  stomachs  from  its  fermentable  nature  than 
the  chemicals  used  to  keep  it  free,  a  reasonable  quantity  might  be 
employed  without  serious  objection.  The  use  of  these  chemicals, 
however,  is  generally  condemned,  and  I  will  merely  mention  a  few 


70  BACTERIOLOGY  IN  CANNING. 

of  them,  because  the  subject  of  bacteriology  demands  the  study  of 
the  actions  of  chemicals  on  germ  life.  Chemicals  are  not  always 
germicidal ;  in  fact,  very  few  have  the  power  to  kill  the  spores,  but 
they  do  have  the  power  of  combining  with  the  oxygen  in  the  differ- 
ent molecules  as  to  make  it  unfit  for  the  vegetation  of  germ  life. 
Salicylic  acid  is  one  of  the  best  known  antiseptics  and  is  easily 
detected  when  used  only  in  small  quantities  by  its  violet  reaction 
in  the  presence  of  ferric  salts.  It 'is  non-poisonous  in  small  quan- 
tities, although  liable  to  injure  persons  afflicted  with  organic  heart 
trouble.  It  has  also  the  medicinal  power  to  reHeve  rheumatism  and 
fermentation  of  the  stomach,  in  which  case  it  is  neutralized  with 
bicarbonate  of  sodium.  It  is  also  used  in  surgery,  and  the  dry 
acid  will  prevent  the  action  of  germs  in  fresh  wounds.  The  com- 
mercial article  is  made  97  per  cent,  pure  from  carbolic  acid,  or^ 
more  properly,  by  passing  carbonic  anhydride  through  sodium 
phenoxide  (carbolated),  heated  in  a  retort,  but  is  improved  by  sub- 
stituting sodium  phenol  in  place  of  sodium  phenoxide,  in  which  case 
all  the  phenol  is  converted  into  salicylic  acid.  At  311^  F.  it  is  con- 
verted back  again  into  its  components.  Its  chemical  or  atomical 
symbol  is  CeH^(OH)CO,H,  or  simplified,  C.H^O,.  The  odor 
of  carbolic  acid  is  plainly  perceptible  when  heated  to  311^  F. 

There  are  many  others,  some  of  which  are  most  deadly  poisons 
to  man  as  well  as  bacteria. 

Carbolic  acid,  corrosive  sublimate,  hydrocyanic  acid  are  among 
these.     There  are  others  which  may  have  value  for  some  things. 

Formic  aldehyde  CH^O  is  a  volatile  antiseptic.  It  volatilizes 
at  212°  F.  Phenol,  thymol,  permanganate  of  potassium,  eucalyptol, 
benzoic  acid,  benzoate  sodium,  terebine,  phenyl-proprionic  acid, 
phenyl  acetic  acid,  boracic  acid,  boroglyceride  and  sulphurous 
dioxide  are  among  the  most  prominent  antiseptics  known.  Some 
of  these  are  extremely  good  for  purifying  utensils,  floors,  ceilings, 
machinery,  etc.,  which  are  used  in  the  manufacture  of  food  products. 

The  liberal  use  of  sulphurous  dioxide  around  the  buildings  is  'a. 
great  safeguard  against  mold. 

We  have  mentioned  in  other  parts  of  this  work  the  preserving 
qualities  of  creosote,  salt  and  sugar. 

The  result  of  the  application  of  these  antiseptics  is  not  always 
germicidal.  As  we  have  mentioned,  they  merely  prevent  the  germs 
from  vegetating,  and  this  may  be  observed  by  transplanting  in  a 
nutrient  medium  free  from  antiseptics. 


CHAPTER  XI. 

HISTORY  OF  CANNING.      DISCOVERIES.      APPERT  OF  PARIS.      ISAAC 

WINSI.OW   OF   MAINE.      THOMAS   DUCKWALI,   AND   AI^BERT 

FISHER   OF   OHIO.      EARLY   CAN   MAKING.      STEAM 

RETORTS.      PROCESSORS  AND 

MANAGERS. 

The  first  we  know  of  canning  is  that  a  Frenchman  by  the  name 
of  Appert,  in  Paris  in  the  year  1810,  discovered  that  it  was  possible 
to  keep  fruits  in  an  air-tight  package  by  boiling,  and  further  history 
of  his  experiments  is  not  available.  In  1839  we  learn  that  Isaac 
Winslow  began  to  can  corn  and  other  products  in  Portland,  Maine. 
He  experimented  largely,  and  for  a  long  time  did  not  succeed  in 
keeping  it  from  spoiling.  He  tried  to  experiment  in  cooking  the 
whole  ears,  but  was  unsuccessful,  and  the  cobs  seemed  to  absorb  the 
sweetness.  He  then  cut  the  corn  from  the  cob  and  boiled  the  cans 
in  a  wash  boiler,  but  nearly  all  his  cans  swelled ;  only  a  few  remained 
good,  which  gave  him  heart  to  experiment  further.  In  1843  he 
built  wooden  process  tanks,  lined  on  the  inside  with  zinc,  and  made 
steam-tight,  so  that  a  moderate  pressure  could  be  maintained,  but 
these  experiments  were  not  entirely  successful  Sometimes  he 
would  be  unable  to  keep  a  single  can.  Along  this  line  of  experi- 
ments he  proceeded,  with  only  a  faint  ray  of  hope,  for  ten  years, 
when  he  applied  for  a  patent,  which  was  allowed,  after  long  delays, 
in  1862.  At  this  time  several  men  in  the  West  began  packing 
fruits  and  tomatoes,  among  whom  were  Thomas  Duckwall  and 
Albert  Fischer,  near  Cincinnati,  Ohio.  Thomas  Duckwall  (who  is 
the  father  of  the  author  of  this  work)  ^  small   way  on  a 

farm  situated  a  few  miles  east  of  Cincinnati,  in  Cleremont  county. 
He  was  eminently  successful  in  keeping  the  various  fruits  and  vege- 
tables, which  brought  good  prices  at  that  time  on  account  of  the 
war.  Meanwhile,  Winslow  was  working  away  on  his  process  of 
keeping  corn,  and  a  part  of  his  application  for  a  patent  on  his  pro- 
cess may  be  interesting.     He  said : 


72  BACTERIOLOGY  IN  CANNING. 

"Alter  a  great  variety  of  experiments  I  have  overcome  the  dif- 
ficuhies  of  preserving  indian  corn  in  the  green  state  without  drying 
the  same,  thus  retaining  the  milk  and  other  juices,  and  the  full 
flavor  of  fresh  green  corn,  until  the  latter  is  desired  for  usd. 
Instead  of  a  hard,  insipid  or  otherwise  unpalatable  article,  I  have 
finally  succeeded  in  producing  an  entirely  satisfactory  article  of  man- 
ufacture in  which  my  invention  consists.  I  have  employed  several 
methods  of  treatment.  My  first  success  was  obtained  by  the  fol- 
lowing process :  The  kernels,  being  removed  from  the  cob,  were 
immediately  packed  in  cans  and  the  latter  hermetically  sealed  so  as 
to  prevent  escape  of  the  natural  aroma  of  the  corn,  or  the 
evaporation  of  the  milk  or  other  juices  of  the  same.  Then  I  sub- 
mitted the  sealed  cans  and  their  contents  to  boiling  or  steam  heat 
for  four  hours.  In  this  way  the  milk  and  other  juices  of  the  corn 
are  coagulated  as  far  as  may  be,  boiling  thus  preventing  the  putre- 
faction of  these  most  easily  destructible  constituents.  At  the  same 
time  the  milk  is  not  washed  away  or  diluted,  as  would  be  more  or 
less  the  case  if  the  kernels  were  mixed  with  water  and  then  boiled. 
By  this  method  of  cooking  green  corn  the  ends  of  the  cans  are 
bulged  out,  as  though  putrefaction  and  the  escape  of  the  resultant 
gases  had  commenced  within  the  cans,  consequently  strong  cans 
are  required. 

"  I  recommend  the  following  method :  Select  a  superior  quality 
of  the  green  corn  in  the  green  state,  and  remove  the  kernels  from 
the  cob  by  means  of  a  curved  or  gauged  knife  or  other  suitable 
means ;  then  pack  those  kernels  in  cans  and  hermetically  seal  the  lat- 
ter so  as  to  prevent  the  evaporation  under  heat  or  the  escape  of  the 
aroma  of  the  corn.  Now  expose  these  cans  of  corn  to  steam  or  boil- 
ing heat  for  about  one  hour  and  a  half  and  then  puncture  the  cans 
and  immediately  seal  the  same  while  hot,  and  continue  to  heat  for 
about  two  and  one-half  hours  longer.  Afterwards  the  can  may  be 
slowly  cooled  in  a  room  at  a  temperature  of  70°  to  100^  F." 

During  this  time  the  canners  in  the  West  were  continually  ex- 
perimenting with  processes  for  preserving  com  and  peas.  Various 
experiments  made  by  Thomas  Duckwall  in  his  small  canning  house 
proved  that  com  and  peas  could  not  be  kept  satisfactorily  by  boil- 
ing the  cans  even  for  hours,  and  to  increase  the  temperature  became 
a  problem  which  was  solved  by  the  use  of  calcium  dissolved  in  the 
boiling  water.  Various  temperatures  were  tried,  and  he  found  that 
by  dissolving  a  certain  quantity  of  calcium  in  a  given  quantity  of 
water  that  240^  F.  could  be  maintained,  and  he  was  successful  in 
keeping  corn  all  the  period  that  the  Eastern  experimenters  were 


BACTERIOLOGY  IN  CANNING.  73 

having  trouble.  He  also  packed  all  kinds  of  fruit  and  berries,  which 
grew  in  abundance  on  the  surrounding  farms,  and  was  kept  back 
only  on  account  of  the  difficulties  in  obtaining  tin  cans,  which  were 
not  manufactured  except  by  hand,  and  in  a  very  crude  way.  Dies 
for  cutting  out  the  tops  and  bottoms  of  the  cans  were  made  of  cast 
iron,  and  the  upper  die  was  made  on  a  huge  weight,  which  was 
pulled  up  to  a  certain  height  by  means  of  a  rope,  and  by  falling  on 
the  sheet  of  tin  would  cut  out  single  tops  and  bottoms.  With  only 
such  crude  machinery  for  making  cans,  the  output  was  compara- 
tively small,  but  the  prices  were  good  and  the  small  frame  house 
began  to  repay  him  for  his  infinite  patience  in  experimenting. 

Between  1867  and  1878  the  corn  packers  in  the  East  had  been 
canning  corn  by  boiling  the  cans  in  water.  The>'  had  not  expe- 
rienced so  much  trouble  as  Duckwall  had  encountered  in  the  West, 
but  were  able  to  keep  a  large  per  cent,  of  their  cans  after  five 
hours'  boiling,  which  process  was  not  successful  in  the  West.  The 
few  manufacturers  in  Maine  at  that  time  suddenly  had  a  very  rough 
experience  in  1878,  when  the  entire  output  spoiled,  nor  were  they 
ever  afterwards  able  to  sterilize  their  cans  by  the  boiling  process. 
Capital  had  been  invested,  and  the  business  had  been  growing  rap- 
idly before,  and  now  everything  seemed  to  be  lost.  New  locations 
were  tried,  longer  times  of  boiling  were  given,  but  without  avail; 
the  corn  seemed  to  have  changed  into  a  new  product  which  would 
not  keep.  Some  manufacturers  sent  samples  to  chemists  for  analy- 
sis to  find  out  what  caused  the  trouble,  but  the  real  cause  not  being 
known,  they  could  not  give  the  manufacturers  any  information  of 
practical  value,  except  that  the  spoiled  corn  contained  small  round 
globules  which  were  not  dissolved  by  boiUng  heat.  In  the  Hght 
of  modern  research  we  cannot  but  give  these  chemists  due  praise, 
from  the  fact  that  Pasteur's  germ  theory  was  not  generally  known 
at  that  time  and  had  few  believers,  even  among  scientists  in  Europe, 
so  the  reports  of  the  chemists  were  remarkable  from  the  fact  that 
they  were  able  at  all  to  locate  the  probable  cause. 

In  1879  a  certain  manufacturer  in  Massachusetts  adopted  a 
new  process.  He  first  boiled  the  cans,  then  punctured  the  cans  and 
finally  gave  them  a  cooking  for  one  hour  in  steam  retorts  or  process 
kettles  at  240°  F.  This  process  proved  satisfactory  for  a  long  time, 
with  only  occasional  spoilage,  due  to  carelessness  in  manufacture. 

We  must  remember  that  the  manufacturers  at  this  time  had  no 
conception  of  the  real  cause  of  the  trouble  in  keeping  the  corn,  but 
looked  upon  the  matter  as  a  mystery,  and  whenever  a  processor 
found  a  method  of  heating  the  goods  in  any  particular  way,  by 


74  BACTERIOLOGY  IN  CANNING. 

which  he  was  more  successful  than  others,  he  was  looked  upon  as 
possessing  secrets,  or  information  on  the  subject  of  keeping  goods, 
and  these  secrets  he  tried  to  conceal  with  a  great  deal  of  mystery. 
He  watched  the  time  of  his  processes  with  great  exactness,  and 
believed  that  one  minute  more  or  less  would  cause  spoilage.  The 
processors  were  in  great  demand,  not  on  account  of  the  actual 
knowledge  they  possessed,  but  on  account  of  what  knowledge  they 
seemed  to  possess.  These  men  had  no  true  knowledge  of  their  busi- 
ness, and  very  few  of  them,  even  to-day,  possess  that  knowledge, 
but  depend  largely  upon  what  they  have  been  told,  or  upon  expe- 
rience. Experience  is  a  good  teacher  so  long  as  no  new  complica- 
tions occur,  but  it  has  been  demonstrated  from  the  beginning  of  the 
business  that  these  new  complications  are  constantly  arising,  and  old 
methods  of  sterilizing  are  not  successful  now.  The  time  is  now  at 
hand  when  manufacturers  see  the  folly  of  depending  upon  mysteri- 
ous rules  for  keeping  their  goods,  and  the  advanced  education  in 
science  is  letting  a  flood  of  light  in  on  the  causes  of  spoilage  in  the 
canning  and  preserving  industries.  Manufacturers  want  to  know 
the  reasons  for  processing  goods  certain  lengths  of  time,  and 
the  necessities  required  for  obtaining  the  best  quality,  and  the 
rule  of  thumb  does  not  satisfy  them.  The  time  is  fast  approaching 
when  the  demand  will  be  made  for  men  with  a  scientific  as  well  as  a 
practical  knowledge  on  this  subject,  so  that  it  now  becomes  a  neces- 
sity for  processors  and  managers  to  take  up  the  study  of  the  science 
of  bacteriology  and  apply  that  science  to  their  work.  The  study  of 
this  science  is  a  difficult  one,  because  it  is  a  complicated  study  and 
so  comprehensive  that  it  usually  requires  the  rudiments  of  a  higher 
education  to  enable  the  student  to  get  the  full  value  and  meaning 
of  what  he  reads  and  sees  under  the  microscope.  Then  again,  there 
are  so  many  branches  of  the  study  that  would  not  have  a  direct 
bearing  upon  this  line  of  business,  so  that  it  would  require  a  great 
deal  of  study  in  all  directions  to  enable  the  student  to  pick  out  the 
points  which  would  be  advantageous  to  this  business.  These 
points  have  been  gathered,  and  the  observations  made  are  of  par- 
ticular value,  both  to  the  manufacturer  and  the  men  who  manage 
the  work,  and  any  one  who  does  not  desire  to  make  a  comprehensive 
study  of  this  science  will  find  that  th^  main  points  have  been  pretty 
well  covered  in  this  work. 

A's,  there  is  a  general  lack  of  knowledge  on  this  subject 
among  canners,  and  a  great  deal  of  misrepresentation  by  certain 
classes  of  men  who  are  doing  the  work  of  managing  and  processing, 
and  as  there  is  a  great  misunderstanding  of  the  principles  and  char- 


BACTERIOLOGY  IN  CANNING.  75 

acteristics  of  bacterial  action,  this  work  will  be  instructive, 
first  to  the  manufacturer  who  wishes  to  become  more  thoroughly- 
acquainted  with  his  business;  secondly,  to  the  managers  and  pro- 
cessors, who  will  do  their  work  with  a  definite  understanding,  and 
the  result  will  be  that  we  shall  have  purer,  cleaner  and  more  whole- 
some goods  than  ever  before,  and  this  result  accomplished  with  less 
loss  from  spoilage. 

CHAPTER  XII 

METHODS  OF  CANNING. 

The  canning  of  sugar  corn  is  one  of  the  largest  industries  in 
the  canning  business,  and  the  consumption  of  this  one  line  alone 
amoimts  to  more  than  30,000  dozen  daily,  and  within  the  last  few 
years  there  has  been  great  advancement  in  methods  and  cleanliness 
of  carrying  on  the  business,  due  in  a  measure  to  improved  machinery 
for  doing  the  work. 

The  varieties  of  corn  now  canned  are  the  "Evergreen"  and 
"F.g\'ptian,"  which  seem  to  be  the  favorite  seed,  because  these  varie- 
ties grow  well  and  produce  a  good  yield.  Good  sound  seed  are  nec- 
essary to  get  a  good  yield  and  great  care  should  be  taken  in  the 
selection.  Planting  should  begin  as  soon  as  the  frost  is  out  of  the 
ground,  and  in  order  to  get  a  longer  season  the  planting  should 
be  made  at  intervals  for  six  weeks  following,  but  not  later,  as  the 
yield  is  not  good.  Corn  requires  good  rich  ground,  properly  fer- 
tilized with  bone  dust  or  black  manure,  in  order  to  get  a  well-devel-* 
oped  ear  and  a  good  yield,  and  the  weeds  should  be  kept  down  and 
the  soil  worked  to  get  good  stout  stalks. 

When  it  comes  time  to  pull  the  ears,  this  should  be  done  in  the 
early  morning  before  the  sun  beats  down  upon  the  com,  the  effect  of 
which  is  to  drive  the  sugar  into  the  cob.  No  corn  should  be  car- 
ried overnight  to  give  a  start  in  the  morning,  but  it  is  the  custom 
among  many  canners  to  do  so.  It  is  usually  worked  up  as  speedily 
as  possible  after  it  arrives  at  the  factory,  and  the  husking  and  sort- 
ing the  good  sound  ears  from  the  worm-eaten  ears  is  the  first  oper- 
ation. The  unsound  ears  are  trimmed  and  then  the  com  is  passed 
into  the  cutting  machines,  which  do  the  work  quickly  and  better 
than  hand  cutters. 

There  are  two  methods  of  packing  corn,  and  we  will  describe 
both  methods,  and  the  cutting  machine  will  prepare  the  corn  for 
either  method,  by  simply  adjusting  the  knives. 


76  BACTERIOLOGY  IN  CANNING. 

MOIST  PACK. 

In  this  method  the  cutting  of  the  com  from  the  cob  resembles 
the  hand  cutting,  as  the  whole  kernels  are  removed  as  nearly  whole 
as  possible  by  the  knives  at  first  cutting,  leaving  very  little  scraping. 

After  the  corn  is  cut  it  is  passes  through  a  wire-screened 
machine  called  a  "silker,"  which  removes  nearly  all  silk  from  the 
mass.  After  the  silking  process  the  corn  is  filled  into  the  cans  cold, 
so  that  the  can  will  cut  open  full  after  it  is  processed.  This  requires 
some  judgment,  because  it  requires  more  corn  when  young  than 
when  it  is  a  little  old.  It  is  needless  to  say  that  the  young  corn  is 
preferable.  Care  should  be  taken  not  to  fill  the  cans  too  full  of 
the  cold  com,  as  it  swells  out  considerably  in  the  cooking  process. 
The  cans  are  then  filled  with  a  weak  brine,  cleaned  and  capped,  but 
not  tipped.  The  next  process  is  the  "exhaust."  The  process  con- 
sists in  immersing  the  cans  in  boiling  water,  which  drives  out  the 
air  and  heats  the  corn.  After  exhausting,  cans  are  then  tipped  and 
delivered  to  the  steam  retorts  or  process  kettles,  which  are  fitted 
with  steam  gauges  and  thermometers,  and  in  these  tanks  they  are 
given  either  a  steam  or  a  water  process  under  pressure  to  obtain  a 
higher  temperature  than  boiling.  The  amount  of  heat  varies  with 
different  canners.  After  this  process  the  cans  are  taken  out  and 
chilled  in  tubs  or  tanks  filled  with  cold  water,  which  stops  the  cook- 
ing process  now  going  on  within  the  can.  This  chilling  process 
keeps  the  corn  from  tuming  dark  or  scorching. 

DRY  PACK. 

This  method  of  canning  corn  is  very  popular  in  Maine,  and 
costs  more  than  the  other  method,  but  the  quality  of  the  pack  is 
better.  The  knives  in  the  cutting  machine  are  set  so  that  the  ker- 
nels are  merely  cut  in  the  middle  and  the  remainder  is  scraped  off 
the  cob  by  the  scrapers  adjusted  in  the  machine.  This  part  makes 
a  pulp  of  the  corn  that  is  scraped  off.  After  passing  through  the 
silker  the  corn  is  placed  in  a  "corn  cooker,"  of  which  there  are  sev- 
eral very  good  ones  in  general  use.  Here  the  grains  and  pulp  are 
cooked  and  filled  into  the  cans  hot  in  a  very  cleanly  manner  without 
any  slopping.  After  the  cans  are  filled  they  are  capped  and  tipped 
at  once,  and  they  are  then  put  into  crates  and  delivered  to  the  steam 
retorts  for  the  sterilizing  process,  and  the  treatment  there  and  after- 
wards is  precisely  the  same  as  with  the  "moist  pack." 

This  method,  while  more  expensive,  produces  a  superior  qual- 
ity of  corn,  and  the  cans  are  more  solidly  packed.     Canners  cut 


BACTERIOI.OGY  IN  CANNING.  77 

open  some  of  their  goods  each  day  to  ascertain  if  the  cans  are  prop- 
erly filled  and  not  darkened  by  carelessness  in  the  final  process. 

WHITENESS. 

The  demands  of  the  trade  have  been  for  the  canner  to  produce 
a  whiter  color  in  his  com,  and  so  urgent  were  the  demands  that  the 
corn  which  cut  open  a  few  shades  darker  than  other  brands  could 
not  command  as  high  a  price.  The  result  has  proved  very  disas- 
trous to  the  canner.  In  order  to  get  his  corn  as  white  as  possible 
he  shortened  his  time  in  the  sterilizing  process,  and  in  some  cases 
he  even  reduced  the  temperature.  The  consequence  was  that 
spoiled  corn  was  prevalent  everywhere.  Many  canners  employed 
chemicals  to  bleach  the  corn,  commonly  sulphite  of  sodium,  which 
produced  the  desired  color  and  greatly  injured  the  flavor.  The 
shortening  of  the  process  and  the  lowering  of  the  temperature  endan- 
gered the  goods,  and  the  sterilization  was  accomplished  by  the  use 
of  germicides,  such  as  salicylic  acid.  Here  a  new  difficulty  arose, 
from  the  fact  that  in  the  presence  of  iron  this  antiseptic  would  show 
its  presence  by  turning  violet  or  purple  in  color,  and  many  are  the 
packers  who  wondered  why  their  corn  turned  purple.  The  exposed 
edges  of  the  tin  would  furnish  enough  iron  to  cause  the  reaction  in 
the  presence  of  salicylic  acid.  Other  germicides  are  also  used,  such 
as  formic  aldehyde,  benzoic  acid,  benzoate  of  sodium,  etc.,  etc.,  with 
the  effect  that  while  the  goods  might  keep  for  a  long  time,  yet  the 
germs  might  not  all  be  killed,  and  in  the  course  of  time  would 
develop,  causing  the  swelling  months  after ;  and  in  the  next  place, 
the  flavor  was  more  or  less  injured  by  the  use  of  such  reagents. 
Thus  a  great  deal  of  poor  corn  flooded  the  market  and  injured  the 
trade  to  the  extent  that  few  persons  cared  to  run  the  risk  of  buying 
the  article  at  all.  The  prices  on  com  fell  rapidly,  and  it  could  be 
bought  for  almost  any  figure  to  get  rid  of  it.  There  were  many 
packers,  however,  who  did  not  allow  the  popular  clamor  for 
extreme  whiteness  to  influence  their  better  judgment,  so  they  con- 
tinued in  the  old  way,  putting  up  the  article  with  a  view  of  obtaining 
the  best  quality  and  giving  the  matter  of  whiteness  only  the  proper 
amount  of  care,  which  can  be  exercised  in  the  best  methods  of  can- 
ning com.  It  is  to  these  packers  that  the  industry  is  once  more 
on  a  proper  relation  with  the  trade,  and  the  cry  for  quality  became 
so  strong  that  the  use  of  bleachers  and  other  reagents  is  rapidly 
coming  into  disfavor,  even  among  former  advocates. 


78  BACTERIOLOGY  IN  CANNING. 

SPOILAGE  IN  CORN. 

The  two  methods  for  canning  corn  described  a  few  pages  back 
seem  to  read  all  right,  but  these  are  now  in  use  and  in  certain  locali- 
ties the  canners  have  been  suffering  severe  losses,  both  from  ''swells" 
and  "sour  corn,"  and  ih  order  to  study  the  causes  and  nature  of  these 
troubles,  let  us  first  understand  just  what  is  meant  by  the  terms 
^'swells"  and  "sour  corn." 

SWELLS  AND  SOUR  CORN. 

Swells  are  the  results  of  pressure  made  from  within  the  cans  by 
various  gases,  such  as  carbonic  acid  gas,  hydrogen,  sulphuretted 
hydrogen,  etc.,  and  in  the  most  of  cases  the  cans  are  sour,  although 
in  several  instances  I  have  seen  sweU.s  in  which  there  was  no  sour- 
ness produced ;  however,  these  are  exceptional  and  occur  only  where 
the  fermentation  was  set  up  by  the  alcoholic  ferments,  such  as  the 
saccharomyces,  cerevisiae  and  ellipsoideus,  etc.  In  these  swells 
the  odor  of  alcohol  was  quite  perceptible.  These  gases,  which  cause 
the  swelling  or  bulging  out  of  the  ends  of  the  cans,  are  the  evidence 
of  fermentation  which  is  set  up  sometimes  by  a  single  variety  of 
bacteria,  but  more  often  by  quite  a  number  of  different  varieties, 
such  as  the  prodigiosi,  amylobacter,  butyrici,  etc.,  which  are  found 
swarming  in  the  anaerobic  state  within  the  can.  The  presence  of 
these  bacterial  forms  may  be  explained  in  this  way :  Either  there  is 
a  small  leak  in  the  can,  or  else  the  sterilizing  process  was  inadequate 
to  kill  off  the  spores  which  developed  afterwards.  Sometimes, 
where  the  leak  is  very  large,  the  cans  may  not  show  by  bulging  out 
the  ends,  in  which  case  the  escaping  fluids  will  be  seen  oozing  from 
the  hole  through  which  the  gases  are  also  making  their  escape.  If 
swells  occur  from  leaks,  there  need  be  no  alarm,  but  if  a  single  can 
is  found  which  swells  without  the  presence  of  a  leak,  there  is  a  rea- 
sonable doubt  about  the  goods  being  properly  sterilized.  Often 
there  has  considerable  time  elapsed  before  swells  make  their  appear- 
ance, in  which  case  it  is  evident  that  the  goods  were  nearly,  though 
not  perfectly,  sterilized.  If  only  a  single  spore  remains  alive,  it  may 
develop  sooner  or  later,  and  if  it  does,  the  can  will  soon  swarm  with 
its  kind.  It  thus  happens  sometimes  that  goods  will  appear  all 
right  for  quite  a  time,  and  then  after  being  agitated  will  swell.  In 
this  case  it  is  a  fact  that  some  forms  have  not  been  killed  and  have 
been  lying  in  a  dormant  condition,  perhaps  on  the  surface  of  the 
contents,  so  that  when  the  can  is  agitated  and  the  spore  is  sub- 
merged, the  fermentation  will  be  certain  as  a  result  of  its  develop- 


OF  THE        ^J 

UNIVERSITY 


.  :^ 


Figure  20 
MAGNIFIED  X  1000. 


MOIyD   FUNGI.      MONILIO   CANDIDA  AND   ASPERGII.I.US   GROWING   WHEN  SUB- 
MERGED  IN   CORN  JUICE.      DEVEI.OPMENT  OE   BUDS 
FROM   CONIDIA. 


BACTERIOLOGY  IN  CANNING.  79 

ment.  This  frequently  happens  when  the  conidia  of  mold  find  a 
lodgment  and  are  not  killed  by  the  heat.  We  have  seen  the  house- 
wife fill  the  fruit  cans  and  seal  them  hot,  and  after  a  time  have  seen 
the  mold  grow  on  the  surface,  especially  if  the  package  happened  to 
be  glass.  So  long  as  the  cans  so  filled  remained  in  a  quiet  state, 
the  contents  would  be  perfectly  sweet,  but  just  as  soon  as  the  can 
was  shaken  sufficiently  to  submerge  the  mold  film,  fermentation 
and  spoilage  would  result,  because  the  mold  would  break  up  the 
sugar  to  obtain  oxygen  for  its  development,  and  thus  resemble  an 
alcoholic  ferment. 

Thus  we  see  that  goods  do  not  necessarily  swell  in  a  short  time 
after  the  final  process,  but  it  is  usually  the  case  if  the  final  process 
does  not  sterilize  the  contents  perfectly.  Whenever  the  process  is 
shortened  and  antiseptics  are  used,  unless  they  be  used  in  liberal 
quantities,  there  is  danger  of  fermentation  and  swells  in  some  future 
time.  If  the  heating  does  not  kill  the  germs  and  the  reliance  is 
placed  upon  the  antiseptic,  unless  that  antiseptic  is  very  powerful, 
the  spores  are  not  killed.  The  effect  of  the  chemical  is  a  reaction 
on  the  oxygen  which  makes  it  unfit  for  the  development  of  those 
spores.  After  a  tiipe,  however,  there  may  be  a  loss  of  power  in  the 
chemical,  in  which  case  the  dormant  spore  will  develop  and  the 
swelling  of  the  can  will  result 

"Sour  corn"  is  a  term  often  misused,  but  its  real  meaning  is  that 
the  corn  within  a  can,  which  has  all  the  appearance  of  being  good  on 
the  outside,  is  found  on  opening  to  be  sour  and  nauseating  to  the 
taste.  Cans  of  sour  corn  will  never  under  any  circumstances 
swell,  otherwise  they  would  come  under  the  heading  of  swells. 

I  have  opened  hundreds  of  cans  of  sour  corn  and  placed  the 
juice  under  the  microscope  to  see  if  there  was  any  bacterial  life. 
I  have  located  the  dead  germs,  but  when  transplanted  to  nutrient 
media  I  have  never  been  convinced  that  any  Hfe  existed,  and  when 
growth  did  appear,  I  was  convinced  after  hundreds  of  experiments 
that  they  came  from  the  air,  and  that  the  germs  found  in  sour  corn 
were  dead.  I  found  that  some  cans  which  did  not  show  a  swelled 
appearance  at  the  time  did  contain  various  living  forms,  but  when 
these  cans  were  put  in  an  incubator  they  would  swell.  The  accom- 
panying plate  will  show  one  view  that  I  obtained  from  a  can  of  this 
kind  of  corn.  This  example  comes  under  the  head  of  swells,  and  is 
not  sour  corn,  properly  so-called. 

This  is,  of  course,  a  view  somewhat  at  variance  with  that 
recently  given  out  by  men  who  claim  to  have  studied  the  subject, 
but  their  errors  were  made  by  not  making  a  proper  distinction 
between  swells  and  sour  corn. 


8o  BACTERIOLOGY  IN  CANNING. 

Sour  corn,  then,  is  a  trouble  which  we  must  locate  in  another 
part  of  the  process  of  canning.  It  could  not  be  due  to  any  imper- 
fection in  the  final  process  of  sterilization,  for  in  that  case  we  could 
be  able  to  induce  a  violent  fermentation  by  incubation.  But  in  the 
case  of  sour  corn  incubation  has  no  effect.  One  thing  may  be 
observed  at  this  point,  however,  and  that  is,  that  when  these  sour 
cans  are  placed  in  warm  water  they  will  bulge  out  slightly,  but  on 
cooling  will  draw  in  again.  In  order  to  explain  this  phenomenon 
we  will  undertake  to  locate  the  place  where  the  souring  occurred. 
You  will  bear  in  mind  that  the  canners  who  have  been  losers  from 
this  trouble  complain  that  a  certain  portion  only  of  their  pack 
sufifered  in  this  way.  Some  say,  "I  lost  about  lo  per  cent,  of  my 
pack ;"  others  say,  "One  quarter  of  my  pack  soured  and  the  balance 
was  good."  These  strange  phenomena  seem  to  throw  a  shroud 
of  mystery  around  the  trouble,  but  the  strangeness  of  it  all  dis- 
appears when  the  light  of  understanding  is  turned  on  the  causes. 

The  cause  of  sour  corn  is  fermentation  which  takes  place  before 
the  final  process  or  sterilizing  process.  I  want  to  impress  this  thought 
upon  my  readers,  and  the  reasons  for  the  statement.  If  the  corn 
is  not  perfectly  heated  in  the  cooker  and  completely  used  out  of  it, 
so  that  none  will  remain  at  blood  temperature  in  the  cooker  for 
any  length  of  time,  and  if  the  cans  are  not  quickly  capped,  tipped 
and  taken  to  the  final  process,  there  is  danger  of  sour  corn.  I  have 
examined  corn  which  came  from  the  cooker  in  a  house  that  was 
having  trouble  with  sour  corn,  and  I  found  that  the  corn  was  some- 
times allowed  to  stand  in  the  cooker  for  quite  a  while,  waiting  on  the 
filling;  that  when  the  filling  of  the  cans  was  going  on  faster  than  the 
capping  facilities,  some  of  this  corn  proved  to  be  in  active  fermen- 
tation when  being  filled  into  the  cans.  I  found  also  the  same  thing 
going  on  in  the  cans  which  sometimes  accumulated  ahead  of  the 
capping  machines.  The  firm  which  was  having  the  trouble  had 
their  capping  machines  get  out  of  order  frequently,  and  when  this 
would  happen  the  com  would  get  sour  in  the  can,  so  that  when 
it  was  sealed  it  enclosed  an  active  fermentation  and  much  gas.  The 
presence  of  this  gas  will  explain  why  the  ends  bulged  out  when  the 
cans  were  afterwards  placed  in  warm  water.  After  the  process 
the  corn  absorbed  the  gases  which  were  sealed  up  in  the  can,  and 
when  heat  was  applied  again  these  gases  expanded,  but  in  a  short 
time  would  be  absorbed  again  on  cooling.  All  this  can  be  readily 
seen  and  understood  if  the  juice  is  examined  under  different  condi- 
tions with  the  microscope,  using  a  lens  of  looo  diameters. 

This  study  of  sour  corn  under  the  microscope  is  very  interest- 


THE   I.ARGE   GERMS  ARE   SACCHAROMYCES.      THE   SMALLER    CELLS   ARE 
MVCODERMA   VINI   SUBMERGED. 


ft*                        — - 

V*.  ^'   ,.: 

^      »                    .*                 .                • 

'-•  -  "-"C      ■  1 

*                                                           '                          !>•• 

-4*                Mo'        X 

"'  ^^  -^y  ■  ^ 

;V.  v?  -I'l  -          " 

'■■      *\               .0           .    *. - 

-•^ 

,>»o              •.                    «*> 

'^si            -       »      :i 

'      VoV -^'S:         ....     .... 

b»o      00                            •.  _    • 

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♦>                          oCP»          »?o 

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0                       Oo» 

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o\,o» 


■  \ 


7 


Figure  21. 
MAGNIFIED  X  1000. 


THE   CLUSTERS   ARE    AMYLOBACTER   AND   LACTIC   MICROCOCCI       THE    SMALL 
RED    DUMBELL    MICROCOCCI    ARE    BLEEDING   BRAST  CALLED   PRODI- 
GIOSI.      THE   INTERIOR    OF  THE   SACCHAROMYCES   REPRESENTS 
THE    SPORES   IMBEDED   IN   THE   PROTO- 
PLASM.     CHAINS   ARE   MYCO- 
DERMA   ACETI. 


BACTERIOLOGY  IN  CANNING. 

ing,  as  the  various  ferments  described  in  the  former  part  of  this 
work,  viz:  Prodigiosus,  butyricus,  lactic  bacillus,  amylobacter, 
mold,  yeasts  or  saccharomyces,  and  an  infinite  number  of  various 
other  forms  which  we  have  not  classified  nor  described,  are  seen, 
and  we  can  become  familiar  with  their  destructive  power. 

STERILIZATION. 

In  order  to  determine  just  what  degree  of  heat  would  be  neces- 
sary to  kill  all  the  bacteria  in  a  can,  I  subjected  numbers  of  cans 
to  various  temperatures  and  these  experiments  were  made  both 
with  corn  in  the  regular  canning — that  is,  just  after  it  came  from 
the  cooker — and  also  with  cans  which  I  inoculated  with  various 
ferments  and  molds.  These  experiments  are  very  interesting  and 
will  give  the  experimenter  a  splendid  idea  of  the  requirements 
necessary  to  keep  corn.  The  following  diagram  will  give  some 
idea  of  what  occurred  with  each  experiment : 


Can  Corn 

Time  of 
Boiling 

Result 

Time 

Tem. 

3  cans 
3     •• 

I     '' 

6     " 
6     " 
6     '• 

6     " 

6     " 

1  hour 

2  hours 

o 

4   i; 
ft   " 

7  " 

8  " 

9  " 
lO       " 

All  spoiled 
<(        (< 

II        II 

II        II 

4  ••               2  kept 
11       <i 

•'        •'        various  times 

5  " 

J3        "                 in  24  hrs. 
2        "                   "  3  Days 
I         ••                   ♦•  24  hrs. 

lo  hours 

<i 

II 

24     '• 
2  Days 
24  hours 

1  Month 

2  Days 

I  Kept 
5     " 

80°  F 

The  results  were  indeed  surprising,  because  two  cans  kept 
all  right  by  boiling  for  five  hours,  and  in  the  experiment  the  next 
day  at  six  hours  all  spoiled.  This  was,  no  doubt,  a  result  of  the 
two  cans  being  free  of  the  more  resistant  forms  of  bacteria.  In 
some  cases  the  cans  did  not  swell  until  nearly  a  month  afterwards, 
which,  no  doubt,  was  due  to  the  presence  of  very  weak  growths  of 
bacteria  or  forms  which  had  nearly  succumbed  to  the  boiling  tem- 
perature. 

I  found  that  a  great  per  cent,  of  those  cans  which  were  boiled 
for  ten  hours  would  keep  all  right,  but,  as  will  be  seen,  one  can  did 
not,  and  a  following  experiment  for  the  same  time  did  not  do  so 
well.  The  sterilization  of  corn,  then,  by  continuous  boiling  is  not 
a  safe  method,  as  the  spores  do  not  perish  at  boiling  temperature. 

I  then  made  careful  experiments  at  220°  F.,  and  the  following 


82 


BACTERIOLOGY  IN  CANNING. 


table  prepared,  giving  the  time  of  processing  with  live  steam  and 
the  results  will  be  interesting: 


No.  of  Cans 

Time 

Results  after  Incubation  at  85°  F 

3 

I 

hour 

All  spoiled  in  24  hours 

3 

2 

2  spoiled  in  24  hours,  i  iu  two  days. 

3 

3 

All  remain  sterile. 

3  others 

3 

All  spoiled  in  24  hours. 

5 

4 

4  spoiled.     I  kept. 

5 

4  kept.     I  spoiled. 

6 

5  spoiled.     I  kept. 

7 

6 

4        ''           3      " 

5 

7 

All  spoiled  in  24  hours. 

The  above  experiments  were  made  when  the  weather  was 
very  warm,  and  the  results  are  not  very  flattering  in  the  temperature 
of  220°  F.  We  notice  the  same  peculiarities  in  these  experiments, 
where  certain  cans  would  keep  and  others  would  spoil  at  the  same 
temperature  used  and  to  all  outward  appearance  were  exactly 
alike,  the  difference,  of  course,  being  that  in  one  lot  there  were 
spores  of  more  resistant  power  to  heat  than  in  others.  These  results 
of  course,  prove  that  220°  F.  is  not  a  sufficiently  high  temperature 
to  sterilize  corn. 

We  cannot  but  marvel  at  the  wonderful  resistant  power  of  these 
spores.  In  the  experiment  in  which  the  temperature  of  220^  F.  was 
registered  throughout  the  contents  of  the  can  for  more  than  six 
hours,  I  found  that  the  spores  of  one  or  two  varieties  were  not 
affected  in  the  least,  and  I  made  a  microscopical  examination  of 
several  cans  after  they  had  begun  to  swell,  and  I  found  nearly 
pure  cultures  of  the  bacillus  amylobacter.  In  some  I  found  the 
bacillus  latici  acidi  and  other  rod-shaped  bacteria  flourishing. 
In  one  can  I  found  a  very  nearly  pure  culture  of  the  bacillus  prodi- 
giosus,  but  no  evidence  of  any  red  pigment.  These  bacteria  I 
transplanted  to  plates  and  they  formed  in  a  short  time  colonies 
which  showed  the  red  pigment  very  plainly. 

I  then  made  more  experiments,  using  a  temperature  of  230^ 
F.,  and  the  results  are  here  given : 


No.  of  Cans  with 
Letters 


Cans  A.  B. 


Results  after  Incubation  at  85°  F 


A  spoiled  in  one  night,  C  in  4  days 

Both  spoiled 

A  and  B  kept.    C  spoiled 

3  kept.     I  spoiled 

2      "        2        " 

All" 

i3  "        I  spoiled 
All  kept 
3  spoiled.     I  kept,     i  leak. 


BACTERIOLOGY  IN  CANNING.  83 

The  above  experiments  were  made  during  a  very  unfavorable 
•condition  of  the  weather.  It  had  been  raining  for  several  days, 
with  the  thermometer  ranging  from  90°  to  100°  F.,  so  that  the  con- 
ditions were  very  favorable  for  fermentation.  I  made  other  experi- 
ments at  230°  F.,  which  were  pretty  good.  A  large  per  cent,  of  these 
experiments  kept  after  three  hours'  heating.  The  unfavorable  con- 
ditions, however,  are  the  best  tests,  because  the  results  would  be 
so  very  damaging  to  the  canner  if  his  goods  were  processed  by 
such  an  unsafe  method.  I  made  several  microscopical  examina- 
tions of  the  cans  which  broke  down,  in  these  experiments,  and 
obtained  almost  pure  cultures  of  several  spore-bearing  varieties. 
One  variety  was  the  bacillus  viscosus,  which  was  flourishing  in  one 
can  along  with  several  rod-shaped  bacilli.  No  doubt  a  great  many 
other  forms  had  been  killed  by  the  heat,  but  these  varieties  still 
remained  alive.  The  bacillus  viscosus  was  not  surrounded  by  any 
envelope  when  I  first  examined  the  juice,  but  after  a  few  hours 
I  noticed  a  slimy,  ropy  appearance;  that  is,  I  could  dip  the  needle 
into  the  fluid  and  lift  it  in  long  threads  like  mucilage.  I  examined 
some  of  this  fluid  again  and  I  found  the  germs  entirely  surrounded 
by  an  envelope  and  in  masses  so  thick  that  it  was  hard  to  get  a 
good  view  without  diluting  the  juice  with  water.  The  most  of  the 
samples  examined  had  a  most  foul  smell,  not  exactly  like  sul- 
phuretted hydrogen,  but  similar  to  it,  and  this  was  caused  by  the 
various  putrefactives,  among  which  was  the  bacillus  fiuorescens 
putidus  and  prodigiosus.* 

I  found  that  a  temperature  of  240°  F.  was  very  destructive  to 
nearly  all  of  the  spores,  but  there  were  many"  cans  which  fermented 
even  after  two  hours  at  this  temperature.  After  three  hours,  I 
have  never  seen  a  can  of  corn  spoil  from  the  spores  which  naturally 
find  their  way  into  the  corn  during  the  process  of  canning,  but 
this  long  time  discolors  the  com  quite  a  good  deal,  and  for  this 
reason  could  not  be  used.  I  have  inoculated  cans  with  the  spore 
of  several  varieties,  among  which  were  the  spores  of  bacillus  sub- 
tilis  and  lactic  acid  bacillus,  which  were  not  killed,  even  at  that 
temperature,  always.  Experiments  in  processing  for  one  hour  have 
not  been  satisfactory,  as  many  cans  would  break  down  and  ferment. 
Experiments  with  a  temperature  of  245^  F.  for  one  hour  have  given 
fairly  good  results,  and  for  one  and  one-quarter  hours  I  have  been 
successful  in  keeping  corn  all  right,  but  the  color  was  somewhat 
darkened.  The  best  temperature  for  sterilizing  com  perfectly  is 
250°  F.  for  not  less  than  fifty-five  minutes,  which  I  have  always 

•It  will  be  well  to  refer  back  to  the  descriptloa  given  the  organiams. 


84  BACTERIOLOGY  IN  CANNING. 

found  to  be  sufficient  to  kill  all  the  spores,  excepting  where  the  cans 
had  been  inoculated  with  the  bacillus  subtilis,  in  which  case  the 
results  were  not  so  satisfactory.  Several  cans  "inoculated 
with  a  pure  culture  of  bacillus  lactici  acidi  also  fermented  after  this 
process,  but  after  one  hour  these  failed  to  develop.  It  requires  at 
least  ten  minutes'  actual  heat  on  the  spores  of  this  germ  at  250^  F.  to 
kill  them.  These  experiments  were  made,  however,  with  the  germs 
which  had  resisted  high  temperatures  previously  and  which  had  been 
taken  from  the  cans  and  cultivated,  so  that  they  represented  the  most 
resisted  high  temperatures  previously  and  which  had  been  taken 
from  the  cans  and  cultivated,  so  that  they  represented  the  most 
resistant  forms.  One  peculiarity  about  the  lactic  ferment  when 
inoculated  into  a  can  of  corn  which  has  been  previously  sterilized, 
is  the  fact  that  it  will  not  be  killed  when  high  temperatures  are 
used,  such  as  250°  F.  for  fifty-five  minutes,  and  that  it  will  decom- 
pose the  corn  without  causing  any  swelling,  by  which  the  sugar 
in  the  milk  of  the  corn  will  be  split  up  into  lactic  acid  without 
forming  any  gases.  The  chemical  change  is  simple  CgHj^O^ 
^— 2C3Hg03.  Of  course  if  any  of  the  spores  of  the  bacillus  subtilis 
be  present  along  with  the  lactic  germ,  hydration  will  take  place  by 
those  forms,  and  the  lactic  acid  will  be  broken  up,  setting  free  certain 
gases  which  will  cause  the  cans  to  swell.  The  lactic  germs  are 
nearly  always  present  in  swelled  corn,  but  rarely,  if  ever,  are  found 
acting  alone,  but  these  forms  make  the  sterilization  of  corn  difficult, 
because  such  high  temperatures  are  required  to  kill  them,  and  there 
is  considerable  danger  of  darkening  the  color,  too,  from  the  em- 
ployment of  high  temperatures.  The  "dry  pack"  corn  is  very  hard 
to  heat  up  to  250^  F.,  as  it  requires  fifty  minutes  by  actual  test  with 
a  self-registered  thermometer  placed  in  the  center  of  the  can. 

REGISTERED  TEMPERATURES. 

The  corn  coming  from  the  cooker  registers  less  than  200^  F., 
usually  about  190°  F.  A  self-registering  thermometer,  sealed  up 
in  the  middle  of  a  can,  and  the  can  processed  for  half  an  hour, 
registered  only  231°  F.,  while  the  temperature  of  the  retort  regis- 
tered 250°  F.  with  fifteen  pounds  pressure.  At  250°  F.  on  the  retort 
another  can  was  processed  forty  minutes  and  the  thermometer  on 
the  inside  registered  only  240^  F.  In  fifty  minutes  another  test 
showed  250°  F.,or  the  same  as  the  thermometer  on  the  retort.  These 
experiments  show  that  the  corn  is  not  a  good  conductor  of  heat 
and  that  all  portions  of  a  two-pound  can  do  not  receive  the  same 
amount  of  cooking.    The  outer  portions  next  to  the  tin  receive  a 


BACTERIOIvOGY  IN  CANNING.  85 

great  deal  more  heat  than  is  necessary  for  steriHzation,  while  the 
center  is  fifty  minutes  in  attaining  the  same  heat. 

From  the  very  nature  of  the  corn,  I  do  not  think  any  practical 
devise  for  agitating  the  contents  will  be  successful,  because  it  could 
not  be  depended  upon  to  expose  the  central  portions  of  the  can  to 
the  heat;  that  is,  I  do  not  think  that  the  corn  can  be  successfully 
shaken  while  heating  to  throw  the  corn  in  the  center  of  the  can  so 
that  it  will  come  to  the  outside,  near  the  tin,  where  the  heat  is 
registered  sooner.  For  this  reason  I  predict  a  failure  for  the  new 
agitation  kettles  now  being  tried.  The  corn  is  too  solid  in  pack 
to  be  thoroughly  mixed  by  any  rotary  motion.  The  best  method 
for  getting  the  heat  to  the  center  of  the  can  more  quickly  would 
be  to  lengthen  the  can  and  decrease  the  diameter,  which  is  a  more 
practical,  method.  However,  corn  which  is  properly  handled  in 
the  final  process  at  250°  F.  for  fifty-five  minutes  need  not  be  dis- 
colored so  much  as  to  make  any  material  difference.  During  the 
process  the  heat  does  not  discolor  the  corn ;  it  is  when  the  cold  air 
strikes  the  tin  that  the  discoloration  takes  place,  and  instead  of  cold 
air,  if  cold  water  is  substituted  by  flooding  the  cans  while  yet  in 
the  process  kettle  after  the  temperature  has  fallen  to  220^  F.  on  the 
thermometer,  there  will  be  no  j>erceptible  discoloration.  The 
scorching  is  caused  by  the  tin  being  struck  with  cold  air,  and 
energy  thus  set  free  scorches  the  corn.  Ice  is  always  coldest  when 
melting ;  metal  is  always  hottest  when  cooling,  especially  when  cold 
air  strikes  it.  The  blacksmith  will  tell  you  how  much  easier  it  is  to 
get  burned  by  iron  which  is  chilling  in  the  air  than  by  a  very  white 
heat.     One  sticks  to  the  flesh  and  the  other  repels  it. 

A  PERFECT  STERIW^ING  PROCESS. 

From  what  we  have  studied  on  the  subject  there  are  two  or 
three  very  important  conclusions  we  can  draw  with  reference  to  the 
very  resistant  forms  of  bacteria  and  the  method  of  killing  these 
forms  without  injuring  the  quality  of  the  goods  to  be  processed. 
We  know  of  at  least  one  form  that  we  cannot  kill  at  250°  F.,  and 
for  all  we  can  tell  there  may  be  others.  I  am  speaking  now  of  the 
spores  or  undeveloped  seeds,  and  dried-up  forms  which  have  not 
begun  to  vegetate.  We  have  seen  that  when  Winslow  began  his 
experiments  he  was  able  to  sterilize  corn  at  the  boiling  tempera- 
ture when  he  applied  that  temperature  for  four  or  five  hours.  For 
some  unaccountable  reason  to  us  none  of  the  resistant  forms  of 
bacteria  seem  to  have  troubled  him;  if  they  had  the  spores  would 
certainly  have  been  just  as  destructive  to  his  corn  as  it  is  to  ours. 


86  BACTERIOLOGY  IN  CANNING. 

It  may  have  been  that  these  forms  had  not  begun  to  attack  sugar 
corn  at  that  time,  it  having  been  cultivated'  in  this  country  only 
for  a  short  time.  It  is  likely  that  the  putrefactive  bacteria  which  at 
this  date  are  so  hard  to  kill  had  been  growing  and  developing 
on  vegetables  and  decomposing  matter  of  an  entirely  different 
character,  so  that  they  had  to  habituate  themselves  to  this  new 
product.  This  is  not  an  uncommon  observation,  taken  of  bacterial 
life,  as  we  frequently  see  this  phenomenon  in  cultures  on  prepared 
media,  where  certain  organisms  start  very  slowly  on  one  kind  of 
substance,  and  then  reproductions  will  flourish  much  more  rapidly 
than  the  parent  germs,  because  they  have  adapted  themselves  to 
the  particular  composition  of  that  substance.  But  to  proceed :  After 
the  boiling  process  had  failed,  and  packers  were  losing  all  the  com 
they  canned,  a  temperature  of  240°  F.,  with  ten  pounds  steam  pres- 
sure, was  substituted  and  the  time  of  cooking  was  reduced  to  about 
one  hour.  This  process  has  been  working  successfully  up  to  within 
the  last  ten  or  fifteen  years,  and  in  some  localities  is  still  successful, 
owing,  perhaps,  to  latitudes  where  these  organisms  occur  in  smaller 
numbers  in  the  atmosphere.  But  the  fact  is,  this  process  has  ceased 
to  give  general  satisfaction,  and  a  still  higher  temperature  of  250^ 
F.,  fifteen  pounds  steam  pressure  for  fifty-five  minutes,  is  now 
declared  to  be  a  perfectly  safe  method  of  sterilization.  Looking  at 
this  matter  from  a  historical  standpoint,  we  would  not  be  surprised 
if  the  time  would  come  when  even  this  extraordinary  heat  would 
prove  inefficient.  As  we  know  that  the  bacillus  subtilis,  which  is 
common  in  infusions  of  hay  undergoing  fermentation,  we  would 
not  be  surprised  if  this  organism  should  habituate  itself  in  com. 
We  must  admit  that  if  we  should  have  to  contend  with  the  spores 
of  this  organism,  whose  proved  resistance  is  over  300°  F.  that  the 
heat  we  are  now  applying  would  have  no  effect  whatever.  I  per- 
sonally have  never  experimented  to  find  out  just  what  temperature 
would  be  necessary  to  kill  these  spores,  but  we  can  rely  on  the  evi- 
dence of  so  eminent  a  scientist  as  Professor  Tyndall,  who  admitted 
his  inability  to  kill  them  by  continuous  heat  at  300^  F.  for  hours, 
not  only  in  one  experiment,  but  in  hundreds.  With  this  evidence 
before  us  we  are  inclined  to  think  that  Klein  and  others  erred  when 
they  said  that  these  spores  could  be  killed  by  ten  minutes'  boiling 
at  120°  C.  This  is  not  probably  the  only  organism  in  the 
world  which  is  so  resistant  to  heat,  and  it  is  well  for  us  to  look 
ahead  for  a  perfect  sterilizing  process,  so  that  when  the  time  comes 
when  we  are  unable  to  keep  goods  by  our  present  methods,  we  may 
have  a  perfectly  reliable  method  to  adopt.  Nor  do  I  think  that  we 
should  wait  until  we  are  forced  by  losses,  but  we  ought  to  begin. 


BACTERIOLOGY  IN  CANNING.  87 

at  once  to  experiment  and  devise  practical  ways  of  carrying  on  this 
jperfect  system. 

We  have  been  referring  to  the  system  discovered  by  Professor 
Tyndall,  which  is  based  on  truly  scientific  principles  and  is  called 
discontinuous  heating.  In  order  to  understand  this  process  and 
its  effect  on  micro-organisms  we  must  refer  back  to  what  we  have 
studied  on  the  vegetation  of  germs  from  spores.  These  small  refrac- 
tile  bodies  that  are  called  spores  are  surrounded  by  two  coats  or 
coverings  which,  like  asbestos,  in  their  power  of  resisting  heat, 
preserve  the  life  within,  except  when  extraordinary  temperatures 
are  used  to  destroy  it.  For  an  example  we  would  refer  to  the  mus- 
tard seed,  which,  in  its  dry  state,  protects  the  life  within  through 
four  minutes*  boiling.  When  these  spores  are  placed  in  a  suitable 
nutrient  medium  they  begin  to  soften  and  expand,  and  the  coatings 
give  away  like  the  bursting  of  a  grain  of  corn  when  it  sprouts,  and 
the  life  witEin  the  spore  begins  to  expand  and  is  soon  surrounded 
with  a  soft  protoplasm  so  delicate  and  sensitive  as  to  perish  when 
even  an  ordinary  boiling  temperature  is  used  against  it.  Just  like 
the  sprout  from  the  grain  of  corn,  the  developing  bacillus  is  sensi- 
tive to  the  heat.  It  is  during  this  vegetative  period  that  we  can 
overcome  the  action  of  bacteria  easiest. 

If  we  boil  our  cans  of  com  for  a  half  hour  the  first  time  and 
chill  them  to  40^  or  50^  F.,  and  keep  them  at  this  temperature  for 
a  few  hours,  many  of  the  spores  will  begin  to  expand  without 
causing  any  fermentation,  so  that  if  we  heat  them  again  for  half  an 
hour  so  as  to  allow  the  can  to  receive  212^  F.  throughout  its  con- 
tents, all  these  developing  spores  will  perish.  After  chilling  and 
storing  again,  some  more  of  the  spores  will  develop,  which  will  be 
killed  in  the  next  heating,  and  on  the  third  or  fourth  heating  they 
will  have  all  perished,  leaving  the  contents  of  the  can  sterile,  and 
the  corn  will  be  almost  as  fresh  as  the  green  product  and  its  white- 
ness never  before  equaled. 

To  the  practical  canner  this  system  of  sterilizing  would  seem 
to  be  almost  out  of  the  question  on  account  of  the  extra  expense 
connected  with  it,  but  I  will  say  that  the  extra  expense  may  be 
entirely  overbalanced  by  the  prices  such  an  article  would  bring  on 
the  market.  As  I  stated  before,  the  time  may  come  when  this 
system  wilf  be  the  only  safe  method  of  sterilization,  and  when  that 
time  does  come,  those  packers  who  have  studied  this  method  and 
experimented  along  this  line  will  get  all  the  best  trade  and  prices 
which  will  repay  them  for  the  extra  expense. 

In  order  to  carry  on  this  work  successfully,  a  cooHng  system 
similar  in  many  respects  to  that  employed  by  brewers  will  have  to 


88  BACTERIOLOGY  IN  CANNING. 

be  used — a  number  of  cooling  cdlars  chilled  with  ammonia  pipes 
to  keep  the  temperature  down  to  between  40^  F.  and  50°  F.  If  the 
number  of  boiling  processes  were  four,  of  course  three  chill-rooms 
would  be  necessary,  and  also  four  sets  of  boiling  or  sterilizing  tanks. 
It  would  also  be  necessary  to  have  quite  a  large  supply  of  cold 
water  in  order  to  chill  the  cans  after  each  boiling  process.  When 
you  think  of  corn  being  kept  by  the  boiling  process  for  a  length 
of  time  not  longer  than  two  hours,  and  realize  what  fine  flavor  and 
white  color  it  would  possess,  surely  the  experiment  will  be  worth 
the  while  for  those  packers  who  are  progressive  and  want  to  pro- 
duce the  best  quality. 

While  speaking  of  quality,  I  want  to  say  that  the  market  never 
has  enough  really  fine  quality  to  supply  its  demands.  It  has  a  great 
deal  more  poor  quality  than  it  demands,  and  one  case  of  poor  corn 
is  a  worse  drug  on  the  market  than  ten  cases  of  good  com  at  higher 
prices.  The  American  people  demand  a  good  quality,  and  if  they 
cannot  afford  to  pay  the  price,  they  buy  poor  goods  which  they  do 
not  relish,  and  consequently  do  not  consume.  It  is  a  trait  of  the 
American  people  that  they  will  have  the  best  quality  even  if  it 
costs  a  little  more  money.  I  believe  our  packers  ought  seriously 
to  consfder  this  method  and  experiiment  along  this  line,  and  thus  be 
prepared  for  emergencies,  which  the  history  of  this  business  demon- 
strates will  surely  come.  Referring  to  the  present  methods  of  pack- 
ing corn,  a  few  suggestions  along  the  line  of  care  would  seem  to 
be  in  order.  As  packers  will  no  doubt  proceed  with  the  higher 
temperatures  for  the  present,  a  few  remarks  on  management  will 
be  beneficial. 

Corn  should  be  pulled  early  in  the  morning  of  the  day  of  de- 
livery, before  the  rays  of  the  sun  drive  the  sugar  into  the  cob  from 
the  kernals.  No  corn  should  lay  overnight  in  the  sheds,  as  fer- 
mentation begins  rapidly,  and  a  great  deal  of  the  natural  sugar  is 
lost  by  standing. 

All  cobs  and  waste  should  be  removed  from  the  vicinity  of 
the  buildings,  so  that  the  atmosphere  may  not  become  burdened 
more  than  ordinarily  with  the  spores  of  bacteria,  which  would 
surely  be  developed  on  said  cobs  and  waste.  From  the  fact  that 
sp>ores  peculiar  to  the  micro-organisms  which  feed  on  corn  are 
present  in  the  shocks  and  on  the  grains  of  com,  it  is  a  very  neces- 
sary thing  that  after  cutting  the  corn  should  be  cooked  as  soon  as 
possible  to  retard  their  action.  After  being  cooked  the  corn  should 
be  filled  into  the  cans  hot  and  thus  find  their  way  to  the  final  process 
as  soon  as  possible  to  avoid  sour  corn,  which  disease  occurs 
right  at  this  point.     The  heating  which  the  corn  receives  in  the 


BACTERIOLOGY  IN  CANNING.  89 

cooker  destroys  all,  or  nearly  all,  developed  bacilli,  but  if  there 
should  be  a  lapse  of  twenty  or  thirty  minutes,  those  forms  that 
were  not  killed  would  create  considerable  acid  by  their  action  on 
the  sugar.    Now  if  the  can  should  be  sealed  in  this  acid  condition, 
the  result  would  be  sour  com.     I  believe  I  have  made  this  subject 
so  clear  that  no  doubt  can  hereafter  exist  as  to  the  causes  of  this 
trouble.    After  rushing  the  cans  to  the  final  process  the  tempera- 
ture, with  dry  steam,  should  be  gradually  raised  to  250°  F.,  with 
only  a  little  exhaust,  but  enough  to  insure  perfect  circulation.     If 
for  any  reason  there  should  happen  to  be  five  or  six  inches  of  water 
in  the  bottom,  from  a  clogging  of  the  exhaust  or  otherwise,  the 
cans  would  not  be  perfectly  sterilized,  even  though  the  thermometer 
should  register  250°  F.  throughout  the  process.     The  circulation 
in  this  case  would  entirely  be  cut  off  from  the  bottom  row,  and  for 
several  rows  of  the  cooking  would    be    very    imperfect    and    the 
swelling  of  these  cans  would  be  a  certainty.     The  upper  courses 
of  cans  would  likely  keep  all  right,  from  the  circulation  of  steam 
due  to  the  pet-cock  under  the  thermometer  exhausting  though  only 
slightly.     The  danger,  however,  to  the  whole  lot  would  be  very 
great  if  for  any  reason  the  exhaust  at  the  bottom  of  the  kettle  should 
become  clogged.     I  have  mentioned  this  feature  of  processing  be- 
cause I  have  seen  the  trouble  happen,  and  the  only  remedy  is  to 
have  a  good,  careful  man  in  charge  of  this  work,  who  would  know 
from  the  actions  of  the  kettle  when  anything  of  this  nature  occurs. 
After  attaining  a  temperature  of  250°  F.  with  a  liberal  exhaust,  the 
escape  of  steam  maybe  lessened  by  closing  the  exhaust  all  but  about 
one  turn,  and  the  temperature  regulated  entirely  by  the  steam  valve 
for  fifty-five  minutes.    When  the  time  is  up,  turn  off  the  steam  and 
allow  it  to  run  down  gradually  to  about  220°  F.,when  the  cans  should 
be  immediately  flooded  with  cold  water  before  the  lid  is  opened.  An 
inch  and  a  half  water  exhaust  in  the  bottom  must  be  opened  at 
once  and  an  overflow  outlet  near  the  top  also.    The  diagram  on  the 
next  page  will  also  show  how  to  operate  these  appliances. 

The  water  line  runs  along  back  of  the  kettles  and  should  be  a 
two-inch  fine  if  possible.  The  connection  to  the  kettle  from  this 
line  should  be  made  with  a  hose  controlled  by  two  valves,  one  at 
the  top  to  prevent  back  pressure  on  the  hose  when  the  steam  is  on, 
and  the  other  at  the  supply  end.  When  the  lid  is  raised  the  hose 
will  bend,  and  this  gives  a  direct  connection  of  water  through  the 
lid  for  this  purpose,  viz :  A  spray,  which  is  done  by  passing  the 
pipe  through  the  lid  and  then  having  an  ell  on  this,  then  a  short 
piece  of  pipe  with  an  inverted  ell,  so  as  to  throw  the  water  against 
the  lid,  and  thus  spray  the  cans  completely  from  the  top.     See 


90 


BACTERIOLOGY  IN  CANNING. 


diagram  W.  Keep  the  water  running  until  it  overflows  from  the 
overflow  pipe,  when  the  cans  will,  no  doubt,  be  chilled  sufficiently 
to  prevent  darkening  in  color.  This  chilling  process  is  a  most  satis- 
factory and  successful  means  of  preserving  the  color  of  com  which, 
under  other  circumstances,  is  darkened  considerably  when  the  cold 
air  strikes  the  can  on  opening  the  kettle.     The  high  temperature 


0V£R  FLOW  RIPE 


EXHAUST 


does  darken  the  corn  just  a  little,  but  by  using  this  chilling  system 
a  whiter  corn  will  be  obtained  than  by  other  methods  where  only 
240°  F.  was  used. 

CORN  TURNING  BLACK   IN  SPOT. 


This  disease  of  corn  has  been  the  cause  of  much  loss  ta 
packers,  and  from  the  nature  of  the  trouble  considerable  mystery 
is  attached  to  it.  Within  the  last  few  years  packers  have  been  puz~ 
zled  to  find,  on  opening  cans  of  corn,  black  spots  here  and  there 
among  the  grains.  "  Those  who  had  been  using  chemicals  for  pre- 
serving the  com,  and  bleaches  to  whiten  it,  naturally  attributed  the 


BACTERIOLOGY  IN  CANNING.  91 

trouble  to  them,  but  when  the  same  thing  repeated  itself  when  no 
chemical  nor  bleachers  were  used,  the  solution  of  the  problem  be- 
came very  compHcated. 

Black  spots  are  of  two  kinds,  and  the  causes  are  two,  viz :  A 
bacterium  called  black  torula,  and  the  action  of  chemicals  and  tin. 
The  first  cause,  black  torulae,  are  bacteria  of  a  black  color  and  the 
product  of  their  fermentation  is  black.  The  action  of  these  ferments 
can  often  be  s^en  right  in  the  corn  field  where  the  ear  has  become 
bruised  and  exposed  to  the  air,  when  a  dirty  tar-black  substance 
will  be  seen  to  cover  the  kernels.  It  is  the  same  organism  that  sets 
up  the  black  rot  in  tomatoes  and  fruits.  If  these  germs  find  access 
to  the  com,  they  will  form  small  colonies  throughout  the  contents 
of  the  can  and  the  spots  will  form  if  any  delays  occur  between  the 
cooker  and  the  final  process.  The  germs  themselves  are  easily 
killed  in  the  process,  but  their  product  will  remain  in  the  can.  When 
the  cause  is  due  to  the  presence  of  these  germs,  the  spots  will  be 
observed  throughout  the  contents  of  the  can  and  not  alone  around 
the  outside  edges.  When  the  black  spots  have  a  purple  tinge,  they 
art  due  to  the  presence  of  salicylic  acid  which  has  had  a  reaction 
on  the  exposed  edges  of  the  tin.  When  the  spots  occur  only  next 
to  the  tin  and  are  black,  they  rr^ay  be  accounted  as  coming  from 
an  action  of  the  acid  on  the  steel,  due  to  a  poor  tin-plating.  There 
are  two  processes  of  plating  steel :  one  is  a  palm  oil  process,  the 
other  is  an  acid  process,  where  the  tin  taken  by  the  sheet  which 
has  been  immersed  in  acid  and  then  passed  through  rollers  to 
squeeze  the  surplus  tin  off.  Some  mills  leave  only  a  shadow  of 
plate  on  the  steel,  using  as  low  as  a  pound  and  a-half  of  tin  to  plate 
a  box  of  steel  sheets.  Under  a  magnifying  glass  this  plating  will 
appear  porous  and  the  steel  is  exposed  to  the  action  of  the  natural 
acid  of  the  canned  product.  The  acid  starts  on  the  steel,  and  of 
course  the  black  spots  will  make  their  appearance.  There  should 
never  be  less  than  three  pounds  of  tin  used  to  the  box  and  this  tin 
should  be  applied  to  the  steel  in  such  a  manner  as  to  entirely  cover 
it.  The  acid  which  is  used  as  a  flux  is  also  dangerous  to  corn,  and 
these  difficulties  due  to  poor  tin-plate  can  all  be  obviated  by  a  chemi- 
cal quantitative  and  qualitative  analysis.  The  spots  caused  by  black 
torulae  can  be  prevented  by  the  oft-repeated  instructions:  "To 
make  the  greatest  possible  speed  with  the  product  from  the  time 
it  comes  in  until  it  reaches  the  sterilizing  process."  The  motto 
should  be  in  the  packing  of  corn :  "From  the  field  to  the  finished 
can  in  the  shortest  possible  time." 


92  BACTERIOLOGY  IN  CANNING. 


PBAS. 

Early  June  peas  are  planted  from  selected  seed  about  April  15, 
and  marrowfats  about  June  i.  The  yield  per  acre  varies,  but  averages 
about  fifty  bushels  per  acre,  producing  about  thirty  dozen  of  two- 
pound  cans.  They  should  be  picked  in  the  early  morning,  and  this 
should  be  done  with  all  products  which  are  canned,  with  no  excep- 
tion; and  the  reason  is^  that  the  product  is  fresher  and  will  be 
sweeter  if  gathered  before  the  hot  sun  beats  down  and  drives  back 
the  sweetness  into  other  parts  of  the  plant.  By  numerous  experi- 
ments this  fact  has  been  demonstrated,  that  during  the  night  the 
sugar  will  follow  the  sap  and  the  sun's  rays  will  drive  a  great  deal 
of  it  back  again. 

When  peas  are  raised  for  canning  they  should  be  planted  on 
ground  close  to  the  factory,  so  that  they  may  be  canned  as  quickly 
as  possible  after  they  are  gathered.  When  they  are  raised  in  con- 
siderable quantities  on  level  ground  the  vines  are  mowed  just  like 
grain  and  taken  to  the  viner,  which  is  a  machine  representing  by 
its  work  the  great  genius  of  its  makers  and  is  one  of  the  most  won- 
derful inventions  of  the  age.  The  vines  are  thrown  into  this  machine 
and  the  clean  peas  are  taken  from  the  end  free  from  bruises  and 
clean  to  a  remarkable  degree. 

After  the  hulling  they  are  taken  to  a  machine  which  separates 
the  four  or  five  sizes  desired,  which  is  probably  the  most  important 
feature  of  canning  peas.  When  the  cans  are  cut  open  the  contents 
must  be  uniform  and  the  size  must  correspond  to  the  wording  of 
the  label.  According  to  the  size  as  well  as  the  quality,  the  prices  are 
graded  in  the  market,  and  it  is  needless  to  say  that  the  smaller  sizes 
bring  more  money. 

After  the  peas  are  graded  they  are  taken  to  the  "blanchers"  and 
scalded  to  get  rid  of  the  mucilaginous  matter  which  covers  the 
skin.  The  outside  of  peas  offers  a  very  fertile  medium  to  the  bacil- 
lus viscosus,  which  will  set  up  fermentation  if  they  be  allowed  to 
stand.  The  blanching  process  cleans  and  heats  the  peas  through, 
after  which  they  are  filled  into  cans  sometimes  by  hand,  but  pre- 
ferably by  machinery  built  for  the  purpose.  These  machines  are 
made  to  graduate  the  quantity  of  peas  for  each  can.  It  is  a  very 
important  matter,  this  filling  of  the  cans,  in  order  that  the  cans  may 
open  with  clear  liquid,  for  if  too  many  peas  are  put  into  the  can 
the  cooking  will  burst  them  and  the  liquid  will  not  be  clear.  Right 
here  I  want  to  say  that  no  packer  should  trust  his  goods  to  any 
machine  without  inspecting  each  step  of  the  process. 

Machines  are  built  to  fill,  brine  and  cap  goods  all  in  one  opera- 


BACTERIOLOGY  IN  CANNING.  93 

tion.  This  should  never  be  done  unless  the  goods  can  be  inspected 
between  each  process.  No  machine  does  perfect  work,  however 
well  it  may  be  planned  and  built,  and  the  man  who  trusts  entirely 
to  machinery  without  experienced  help  to  inspect  each  process,  is 
liable  to  have  loss  on  account  of  poor  quality,  the  result  of  imper- 
fections. It  is  a  far  wiser  plan  to  have  separate  machines  for  each 
process,  and  where  peas  are  filled  by  machinery  they  should  be 
inspected  and  doubtful  cans  weighed. 

After  filling,  brining  and  sealing,  with  as  much  dispatch  as 
possible,  the  cans  are  ready  for  the  last  and  most  important  part 
of  the  work,  the  sterilizing  and  cooking  process,  which  is  done  at 
a  temperature  of  240°  F.,  with  a  time  depending  entirely  on  the 
nature  of  the  peas.  If  the  peas  are  young  and  tender,  which  should 
be  the  case  if  the  business  has  received  the  proper  care,  this  tem- 
perature maintained  for  fifteen  minutes  will  both  sterilize  and  suf- 
ficiently cook  them  without  any  danger  of  bursting  the  peas. 
Young  peas  will  take  this  temperature  in  a  very  short  time,  as  they 
are  not  very  resistant  to  heat,  like  corn.  Experiments  go  to  show 
that  240°  F.  will  be  registered  throughout  the  can  in  about  ten 
minutes  and  all  organisms  which  are  peculiar  to  peas,  the  most 
common  of  which  is  the  bacillus  viscosus,  will  be  destroyed.  Mar- 
rowfats and  old  peas  require  about  double  the  time  that  the  young 
peas  are  given. 

The  peculiar,  slimy  and  ropy  appearance  sometimes  seen  in 
peas  is,  like  sour  corn,  due  to  the  bacterial  action  between  the 
blanching  and  sterilizing  process,  and  this  must  be  always  the  case 
where  the  cans  are  allowed  to  stand,  due  to  overcrowding  or  un- 
necessary delays  or  breakdowns.  The  packer  must  understand 
that  there  must  positively  be  no  delays  here,  he  must  have  reserve 
machines  to  avoid  this  in  any  line  of  goods  he  is  packing. 

Of  course,  if  the  sterilizing  process  is  not  sufficient,  the  can 
will  swell,  and  if  too  long  the  peas  will  be  overcooked  and  the 
liquid  will  be  muddy.  So  great  care  must  be  exercised  to  get  just 
the  happy  medium.  Care  must  be  exercised  all  along  the  line,  and 
no  packer  should  be  without  a  competent  manager,  who  is  up  on 
all  these  points.  I  might  go  even  further  and  say  that  the  packer 
should  in  the  near  future  demand  that  his  superintendent  should 
have  some  knowledge  of  bacteria  before  trusting  his  capital  to  men 
without  the  proper  knowledge  to  prevent  loss.  Under  no  circum- 
stances should  peas  be  colored,  either  by  artificial  coloring  matter 
or  by  heating  them  in  copper.  If  there  is  a  demand  for  very  green 
peas,  be  brave  enough  to  say  No.  If  peas  are  vined  at  the  proper 
time,  and  speed  and  care  used  throughout  the  system,  no  color  will 


94  BACTERIOLOGY  IN  CANNING. 

be  necessary.  They  will  open  green  enough  in  appearance  and 
will  be  entirely  free  from  poisons. 

There  is  nothing  which  can  bring  discredit  upon  a  business 
quicker  than  adulterations,  and  while  the  public  demands  that  the 
product  shall  be  a  good  color,  by  all  means  give  it  to  them,  but  do 
not  resort  to  artificial  means.  What  the  consumer  wants,  is  not  so 
much  the  color,  but  the  standard.  If  the  standard  is  good  the 
color  will  be  all  right,  and  this  is  why  the  consumer  wants  the 
good  color,  because  naturally  it  is  associated  with  good  quality. 
Canners  have  a  great  deal  to  contend  with  to  please  the  trade,  but 
in  order  to  win  for  the  industry  the  confidence  and  respect  of  the 
people,  two  things  must  be  observed — honest  goods  and  cleanliness 
of  the  work. 

It  is  with  the  hope  that  many  of  the  evil  effects  of  the  violation 
of  these  two  points  will  be  remedied  that  this  work  is  given  to  the 
canner.  We  will  uphold  only  honest  methods,  and  to  be  exempt 
from  spoiling,  due  to  bacterial  action,  you  must  be  very  clean  in  the 
work. 

TOMATOES. 

It  is  not  the  purpose  of  the  writer  to  give  formulae  for  packing 
the  various  kinds  of  goods,  only  so  far  as  the  keeping  qualities  are 
concerned,  because  each  packer  has  his  own  ideas  of  how  he  wishes 
to  pack  his  goods ;  but  the  principle  of  keeping  those  goods  are  not 
always  apparent.  Some  packers  do  not  exhaust  their  tomatoes, 
merely  fill,  seal  and  process ;  others  leave  the  vents  open  and  then 
tip  the  cans  before  processing;  others  steam  the  filled  cans  before 
capping  in  steam  boxes.  In  point  of  flavor  the  first  method,  no 
doubt,  gives  the  best  results,  but  the  tomatoes  must  be  rushed 
through  quickly  from  the  time  of  scalding  to  the  sterilizing  process, 
as  fermentation  begins  very  quickly  after  scalding. 

The  scalding  of  tomatoes  is  a  very  important  feature  of  tomato 
canning.  This  should  be  done  when  the  water  is  boiling  and  jump- 
ing, then  ft  will  scald  the  peel  without  heating  the  tomato  to  the 
center.  If  the  water  be  not  boiling  hard,  the  tomato  will  be  partially 
cooked  and  heated  through  before  the  skin  will  loosen.  Frequently 
it  will  be  noticed  that  a  great  deal  of  meat  will  come  ofif  with  the 
skin,  when  the  water  was  not  at  the  proper  temperature.  If  the 
tomatoes  leave  the  scalder  whole  and  firm,  the  skin  will  be  easily 
removed  and  fermentation  will  not  begin  so  soon.  If  the  tomatoes 
be  filled  into  cans  promptly  and  processed  at  240°  F.  for  ten  minutes, 
the  sterilization  will  be  all  right,  but  the  cans  will  not  draw  in  as 


Figure  22 
MAGNIFIED  X  icoo. 

TOMATO  JUICE  FERMENTING. 
SACCHAROMYCKS,    BUTYRICUS,    PRODIGIOSUS    AND    I.ACTiC    BACII.1. 


LI 


BR^ 


UNIVERSITY 


Figure  23 
MAGNIFIED  X  1000. 
TOMATO  JUICE   FERMENTING. 
A — IvS  A   CHAIN    MYCODERMA    ACETl. 

Same  as  No.  r  at  2.20. 


BACTERIOLOGY  IN  CANNING.  95 

rapidly  as  in  the  other  system,  where  the  cans  were  exhausted.  If 
properly  sterilized,  however,  the  goods  will  keep  and  the  cans  may 
be  snapped  back  to  their  natural  shape  by  the  boys  who  pile  them. 
The  tomatoes  packed  in  this  manner  are  very  superior  in  quality 
and  flavor,  but  require  good  management  and  dispatch  in  handling 
throughout,  in  order  to  prevent  sour  tomatoes,  which,  like  sour 
corn,  are  most  disagreeable  in  taste. 

A  very  common  method  of  packing  tomatoes  is  in  the  use  of 
steam  boxes,  where  whole  truck  loads  are  pushed  into  them  and 
allowed  to  steam  for  about  ten  minutes  before  capping.  There  is 
great  danger  in  this  method,  especially  if  allowed  to  accumulate 
ahead  of  the  capping  machine,  and  two  views  taken  of  the  juice 
which  was  thus  exposed  for  over  half  an  hour  will  be  interesting. 
Fermentation  started  almost  as  soon  as  the  cans  left  the  steam 
boxes,  and  I  made  an  examination  about  fifteen  minutes  after,  and 
again  in  twenty  minutes  after  that,  and  the  development  in  that 
short  time  was  marvelous.  By  comparing  Fig.  22  with  Fig.  23  the 
propagation  may  be  observed  in  the  case  of  each  cell. 

The  great  danger  in  allowing  these  tomatoes,  which  have  been 
heated,  to  stand  for  any  length  of  time  is  clearly  seen  by  the  micro- 
scopic views  we  have  taken.  We  know  that  the  result  would  be 
sour  tomatoes  if  the  cans  should  be  processed  while  this  fer- 
mentation is  going  on,  for  the  acids  formed  would  be  sealed  up,  and 
also  whatever  gases  were  present  when  the  cans  were  sealed. 

Packers  have  often  noticed  that  tomatoes  would  sometimes 
spoil  if  moved  about  from  one  place  to  another.  This  is  probably 
due  to  the  presence  of  mold  conidia  on  the  surface  of  the  juice  in 
the  can,  due  to  imperfect  sterilization  or  perchance  a  slight  leak 
when  the  fungus  has  started  to  grow  on  the  surface,  having  been 
drawn  into  the  can  through  the  leak.  As  long  as  the  fluid  is  not 
shaken  the  fungus  will  grow  on  the  surface  without  causing  any 
fermentation,  and  also  keeping  back  any  other  forms  which  might 
happen  to  find  a  lodgment  on  the  surface ;  but  if  the  can  be  moved 
and  shaken,  the  swelling  is  only  a  matter  of  a  very  short  time,  as 
fermentation  will  commence  at  once,  with  perfect  resemblance  to 
true  alcoholic  fermentation.  The  reason  that  tomatoes  will  spoil 
when  agitated  is  nearly  always  due  to  mold  conidia,  and  when  they 
are  heated  and  filled  into  cans  at  home,  the  air  space  will  contain 
enough  spores  to  start  the  growth  of  a  pencillium  on  the  surface. 
If  the  cans  are  carried  to  a  dark,  cool  place  and  not  disturbed,  they 
will  not  spoil,  but  if  shaken  will  ferment  rapidly. 

Tomatoes  are  used  not  only  for  canning,  but  in  the  preparation 


96  BACTERIOLOGY  IN  CANNING. 

of  table  condiments,  such  as  soup,  catsup,  chili  sauce,  chutney, 
etc.,  and  it  may  truly  be  said  that  the  tomato  is  the  most  popular 
vegetable  grown  for  food. 

SWEET  TOMATO   CATSUP,    CHILI   SAUCE,   CHUTNEY. 

The  tomato  is  a  very  perishable  vegetable,  easily  attacked  by 
bacteria,  very  susceptible  to  the  growth  of  mold,  on  account  of  its 
sweet  acid  juice  which  forms  a  very  large  per  cent,  of  its  make-up. 
It  is  this  juice  which  makes  it  so  valuable  for  catsup  purposes.  The 
juice  and  meat  of  the  tomato  are  forced  through  a  screen  and  a  com- 
mercial article  called  tomato  pulp  is  preserved  and  sold  for  making 
catsup. 

On  account  of  the  very  fermentable  nature  of  tomatoes,  this 
pulp  is  hard  to  keep,  except  in  hermetically  sealed  packages,  which 
must  be  sterilized.  On  account  of  its  being  a  good  medium  for  the 
growth  of  the  molds,  such  as  aspergillus  glaucus,  pencillium  mucor, 
racemosus,  mycoderma  vini  and  monilia  Candida,  this  pulp  can- 
not be  put  up  in  hermetical  packages  without  spoiling,  unless  these 
packages  be  given  a  sterilizing  after  sealing.  It  has  been  a  very 
common  method  to  add  an  antiseptic  to  tomatoes  while  cooking, 
and  thus  preserved,  the  juice  could  be  sealed  up  hermetically  and 
would  keep  fairly  well,  although  not  perfectly,  as  the  antiseptic 
could  not  be  used  in  quantities  of  sufficient  power  to  destroy  germs 
without  injuring  both  the  flavor  of  the  goods  and  the  health  of  the 
consumer. 

Salicylic  acid,  which  is  a  very  powerful  and  tasteless  germicide, 
has  been  used  for  this  purpose,  but  the  laws  of  several  States  have 
been  made  so  stringent  against  its  use  on  account  of  complica- 
tions which  made  their  appearance  in  some  persons  affected  with 
heart  trouble.  By  the  use  of  this  and  other  germicides,  it  was 
easy  to  barrel  up  the  juice  of  tomatoes  which  could  be  kept  and 
made  up  into  catsup  whenever  it  was  wanted. 

This  tomato  juice  is  made  into  catsup,  which  in  its  turn  must 
be  kept  from  the  action  of  bacteria  by  some  germicidal  reagent, 
because  it  cannot,  according  to  present  methods  of  bottling,  be 
made  to  keep,  nor  can  it  be  sterilized  because  the  cork  would  not 
keep  out  the  germs.  On  cooling  a  vacuum  of  such  power  is  pro- 
duced that  air  is  sucked  in  through  and  around  the  cork,  and  this 
air  may  have  in  it  the  spores  of  bacteria  which  will  begin  fermen- 
tation in  the  goods  at  once,  unless  it  is  armed  against  the  attack 
with  a  powerful  antiseptic. 

Another  reason  why  catsup  and  chili  sauce  are  usually  given 


BACTERIOLOGY   IN  CANNING.  97 

some  antiseptic  to  keep  them  is  the  fact  that  when  once 
opened  these  articles  would  either  have  to  be  consumed  the 
same  day  or  else  kept  on  ice  to  prevent  fermentation. 

I  have  sealed  catsup  and  boiled  it  for  an  hour  and  then 
covered  the  cork  with  sealing  wax,  but  it  would  almost  in- 
variably spoil  unless  some  germicide  were  used  to  make  the 
oxygen  in  the  contents  unfit  for  bacterial  food.  I  made  an 
examination  of  some  catsup  I  had  tried  to  preserve  without 
antiseptics,  and  the  result  was  a  formation  of  mold  on  the 
surface. 

Indeed,  I  have  found  that  molds  are  the  chief  obstacles 
in  the  manufacture  of  pulp,  catsup  and  chili  sauce  without 
antiseptics,  nor  can  their  action  always  be  prevented  by  the 
use  of  antiseptics  unless  used  in  very  large  quantities.  The 
frequent  losses  to  manufacturers  in  these  lines  will  verify 
the  truth  of  the  statement. 

During  very  warm  days  after  rains,  sometimes  the 
molds  will  develop  so  rapidly  on  the  tomatoes  that  they  can- 
not be  used  up  before  the  fungus  becomes  visible  to  the 
naked  eye.  The  conidia  are  very  resistant  to  heat  and  it  is 
sometimes  very  hard  to  preserve  catsup,  chili  sauce,  etc., 
during  such  times,  even  with  the  aid  of  germicides. 

Looking  over  the  business  as  carried  on;  that  is,  by  the 
use  of  antiseptics  to  keep  the  goods,  I  cannot  but  say  that 
it  is  risky,  because  a  quantity  sufficient  for  the  killing  of 
ferments  cannot  be  used  without  injuring  the  flavor  of  the 
goods  and  endangering  the  health  of  the  consumer.  Owing 
to  the  non-expansion  of  glass,  bottles  cannot  be  sterilized  so 
readily  as  tins,  so  that  the  keeping  of  catsup,  chili  sauce, 
etc.,  becomes  a  problem. 

The  manufacture  of  tomato  catsup  from  unfermented 
material  is  a  very  great  industry  at  this  time,  and  the  form- 
ulae in  use  by  great  concerns  are  proprietary  and  should  not 
become  public  property.  As  different  concerns  have  their 
own  peculiar  methods,  which  they  consider  better  than 
others,  any  formula  which  might  be  suggested  would  be 
open  to  criticism,  and  it  is  not  the  purpose  of  this  work  to 
take  up  the  different  ingredients  which  go  to  make  up  any 
particular  food  product,  but  simply  to  point  out  the  dangers 
from  bacterial  action  and  give  the  necessary  precautions  to 
prevent  loss. 

It  is  my  impression  that  tomato  catsup  and  chili  sauce. 


98  BACTERIOLOGY   IN   CANNING. 

also  chutney,  can  be  put  up  without  the  use  of  antiseptics, 
which  would  no  doubt  give  a  better  flavor  to  those  condi- 
ments, but  we  must  not  overlook  the  fact  that  the  consumer 
will  have  to  be  careful  and  keep  these  products  in  a  cool 
place  to  prevent  fermentation.  When  a  good  method  of 
sterilizing  these  goods  in  glass  is  discovered,  the  dangers 
which  beset  the  manufacturers  who  use  antiseptics  will  be 
obviated  to  a  great  degree. 

It  is  argued,  in  opposing  the  use  of  antiseptics  in  food 
products,  that  because  nearly  everything  now  prepared  for 
table  use  is  preserved  chemically,  so  much  may  be  taken 
from  different  articles  of  food  at  a  single  meal  as  to  inter- 
fere with  the  natural  peptonization  of  that  food  in  the  stom- 
ach during  the  process  of  digestion  under  the  influences 
of  saliva,  gastric  juice,  bile  and  pancreatic  juice.  This  ar- 
gument has  such  force  that  laws  have  been  passed  in  sev- 
eral States  and  European  countries  prohibiting  the  sale  of 
such  goods  altogether,  and  in  a  few  instances  only  when  the 
packages  are  labeled  ^'compounds,"  or  '^chemically  pre- 
served." It  is  hard  to  draw  the  line,  however,  because 
there  are  several  articles  which  are  preserved  by  antisep- 
tics to  which  no  reasonable  man  could  object.  Smoked 
meats  are  preserved  from  the  creosote  taken  from  the 
smoke,  and  we  find  that  the  honey  bee  preserves  its  honey 
by  injecting  formic  acid. 

I  am  inclined  to  think  that  in  a  general  way  antiseptics 
of  certain  kinds  are  not  injurious  to  man,  but  I  do  think 
that  there  ought  to  be  limitations  only  in  the  use  of  chemi- 
cals to  such  goods  as  cannot  be  kept  free  from  the  action  of 
the  bacteria. 

For  instance,  in  a  chemical  analysis  of  a  great  many 
varieties  of  canned  goods  by  Government  chemists,  they 
discovered  the  presence  of  salicylic  acid  in  nearly  all. 
Every  thinking  man  will  agree  that  this  is  unnecessary  for 
keeping  goods  packed  in  tin,  because  the  simple  sterilizing 
process  was  all  that  was  required  to  keep  canned  goods. 
Salicylic  acid  was  used  in  corn  so  that  the  corn  might  be 
whiter,  because  a  shorter  process  would  keep  it  when  the 
germicide  was  present.  It  is  the  abuse  of  privileges  which 
brings  down  the  wrath  of  the  law  upon  all. 

While  I  think  that  it  is  possible  to  keep  the  most  of 
goods  without  the  use  of  antiseptics,  I  am  not  ready  to  con- 


Figure  24 
MAGNIFIED  X  1000. 

PENCILLIUM,   ASPERGli:.I,US,   GI^AUCUS  AND  SOME  OF  THE  CONIDIA. 


V^  OF  THB  r 

aNIVERSITY 


BACTERIOLOGY    IN   CANNING.  99 

demn  their  use  in  some  cases,  for  it  is  vastly  more  injurious 
to  the  human  stomach  to  receive  foods  which  are  undergo- 
ing fermentation  than  to  receive  foods  which  are  free  from 
that  fermentation,  even  if  they  are  preserved  by  small  quan- 
tities of  harmless  germicides.  The  disorder  to  the  stomach 
would  be  infinitely  greater  in  the  former  case. 

I  have  seen  thirty  grains  of  salicylic  acid  taken  daily 
for  a  whole  month  without  any  perceptible  inconvenience 
to  the  man,  and,  indeed,  we  might  go  still  farther  and  state 
that  foods  chemically  preserved  are  sometimes  very  bene- 
ficial to  sufferers  from  stomach  troubles,  as  they  retard  the 
action  of  foreign  ferments  and  allow  the  peptonizing  pro- 
cess to  go  undisturbed.  Foods  which  cannot  ordinarily  be 
sterilized  and  kept  are  better  if  preserved  with  some  harm- 
less antiseptic,  and  we  might  include  under  this  head  toma- 
to catsup,  chili  sauce  and  chutney,  because  after  they  are 
opened  they  become  exposed  to  bacterial  action,  and  the  an- 
tiseptics would  prevent  this  for  quite  a  time  at  least. 

CREAM   OF  TOMATO  SOUP. 

The  canning  of  this  article  is  quite  extensive  and  the 
formulae  are  proprietary,  but  from  the  milk  used  in  the  man- 
ufacture the  loss  occasioned  is  sometimes  alarming.  In  this 
article,  as  well  as  other  products  where  milk  is  used,the  dan- 
ger from  lactic  fermentation  caused  by  the  bacilli  lactici 
acidi  and  bacilli  cyanogeni,  which  give  the  blue  color  to 
milk,  is  very  great. 

When  these  organisms  get  a  start  the  loss  is  generally 
complete,  nor  is  their  action  perceptible  until  too  late  to 
save  the  goods.  There  is  no  swelling  or  bulging  of  the  cans 
to  indicate  that  they  are  at  work,  and  it  is  only  when  their 
work  has  progressed  far  enough  to  be  noticeable  that  it  can 
be  detected  except  by  chemical  analysis  for  lactic  acid. 
These  germs  break  the  sugar  into  lactic  acid  without  any 
other  chemical  change,  and  on  account  of  the  usual  boiling 
process  they  are  generally  the  only  forms  left,  and  conse- 
quently in  almost  all  cases  the  work  is  accomplished  by  pure 
cultures.  The  boiling  or  sterilizing  process  will  kill  off  all  the 
ordinary  forms  of  bacteria  and  only  these  will  remain  because 
of  their  great  resisting  power.  Some  packers  have  resorted  to 
the  use  of  germicides  to  keep  this  soup,  because  it  appeared 
that  it  was  not  possible  to  sterilize  it,  but  such  is  not  the 
case;  it  may  be  sterilized  in  a  short  time  under  proper  pre- 


100  BACTERIOLOGY   IN   CANNING. 

cautions  by  two  methods,  either  the  discontinuous  process 
or  130°  C.  for  fifty  minutes.  The  organisms  which  cause 
this  trouble  are  non-motile,  and  you  would  never  suspect 
the  terrible  damage  they  were  doing  unless  you  knew  the 
character  of  the  organism. 

OYSTERS. 

'Che  oyster  beds  in  Chesapeake  Bay  cover  hundreds  of 
thousands  of  acres,  and  the  dredging  gives  business  to  over 
fifteen  hundred  vessels  and  eleven  thousand  people,  while 
those  directly  and  indirectly  interested  are  about  one  hun- 
dred and  fifty  thousand. 

The  packing  of  oysters  begins  in  October  and  runs 
through  the  winter,  finally  ending  about  the  last  of  March. 

The  oysters  in  shells  are  brought  in  fresh  and  steamed 
in  steam  cans,  after  which  they  are  shucked,  washed  an4 
filled  into  boxes  by  weight  regulated  by  law.  The  cans  are 
hot  dipped,  capped  and  given  a  heavy  process  of  from  ten 
to  fifteen  minutes  at  240°  F. 

The  only  place  where  considerable  care  must  be  exer- 
cised in  the  packing  of  oysters  is  after  they  are  shelled.  If 
exposed  to  the  atmosphere  for  any  length  of  time,  bacteria 
of  a  pathogenic  nature  may  find  a  lodgment,  and,  if  allowed 
to  begin  their  action,  will  produce  ptomaines.  There  is  dan- 
ger to  a  certain  extent  also  with  the  oysters  in  the  shell  be- 
fore steaming  if  they  be  not  fresh  and  cold.  No  diseased 
oysters  should  be  used,  none  that  may  be  slightly  tainted, 
for  if  these  poisons  are  once  deposited,  or,  more  properly, 
produced,  the  results  will  be  damaging  in  the  extreme,  may 
even  cause  the  death  of  the  consumer. 

The  word  of  warning  given  here  is  not  ill-timed;  there 
have  been  cases  where  packers  of  oysters  have  put  up  oys- 
ters which  ought  to  have  been  buried  and  we  frequently 
read  of  whole  families  stricken  with  terrible  cramps  and 
sickness  as  a  result  of  eating  contaminated  canned  goods. 
This  is  damaging  to  the  business  in  general,  and  this  warn- 
ing should  be  sufficient  to  keep  any  man  from  willfully  can- 
ning oysters  or  anything  else  which  may  have  become  con- 
taminated. 

MEATS   AND   FISH  IN  GENERAL. 

There  are  many  ways  in  preserving  and  canning  these 
articles  which  have  caused  the  growth  of  various  mammoth 


BACTERIOLOGY   IN   CANNING.  101 

establishments  to  produce  a  supply  sufficient  for  the  de- 
mand. The  canning  of  beef,  sausage,  clams,  lobster,  salmon, 
sardines,  etc.,  represents  millions  of  invested  capital,  to  say 
nothing  of  the  various  other  methods  of  preserving  by  dry- 
ing, smoking,  pickling,  etc. 

The  canning  of  meats  and  fish  of  every  description  is 
easily  done,  and  there  will  be  no  difficulty  if  they  are  fresh 
and  rushed  through  rapidly  after  the  first  heating  and  given 
a  heavy  process,  varying  with  different  kinds  of  meat. 
Only  the  ordinary  precautions  are  necessary  as  described  in 
the  sterilizing  processes  of  other  goods. 

Probably  no  line  of  canned  goods  has  caused  so  much 
trouble  as  the  canning  of  meats  and  fish.  There  have  been 
hundreds  ot  cases  where  people  have  been  stricken  down 
and  died  from  eating  canned  goods  of  this  kind,  because  of 
the  presence  of  ptomaines.  Meat  is  very  susceptible,  and 
fish  even  more  so,  to  the  action  of  pathogenic  germs.  Even 
meat  canned  from  animals  suffering  with  some  disease  may 
contain  these  tox-albumenoids,  and  it  sometimes  happens 
that  unscrupulous  persons  will  try  to  evade  the  law  and 
will  persist  in  canning  meat  which  they  know  ought  to  be 
condemned,  I  know,  personally,  of  one  man  who  was  ar- 
rested time  and  time  again  for  trying  to  can  meat  which 
was  wholly  unfit  for  food.  The  dangers  attending  these 
cases  are  very  great,  and  anyone  who  does  try  to  evade  the 
law  should  be  dealt  with  in  a  very  summary  manner. 

During  the  process  of  canning  meats  and  fish,  the  dan- 
gers from  ptomaines  is  very  great  unless  everything  is  done 
with  dispatch.  The  juice  of  meats  is  probably  the  most  nu- 
tritious medium  for  the  spontaneous  growth  of  micro-or- 
ganisms. Not  only  common  putrefactive  germs  will  begin 
action,  but  even  pathogenic  bacteria  will  thrive  remarkably 
well  and  most  rapidly,  too,  in  a  favorable  temperature. 
Meat  should  always  be  kept  very  cold,  which  is  an  unfavor- 
able condition  for  the  propagation  of  bacteria. 

One  fact  must  stand  out  clearly  to  packers  of  meats  and 
fish:  **No  amount  of  processing  and  no  quantity  of  antisep- 
tic will  dispose  of  ptomaines  after  they  have  been  pro- 
duced." 

Another  method  of  preserving  meat  so  that  bacteria  will 
not  attack  it  is  by  salting.  Salt,  when  used  in  sufficient 
quantities,  will  make  the   conditions  unfavorable  for  the 


102  BACTERIOLOGY   IN   CANNING. 

propagation  of  bacteria.  This  method  is  carried  on  exten- 
sively by  pork  packers  and  fish  packers,  and  the  market  for 
this  class  of  goods  is  very  large. 

Another  method  of  preserving  meat  is  by  smoking.  This 
is  also  carried  on  with  fish,  such  as  herring,  sturgeon,  hali- 
but and  cod.  The  preserving  of  smoked  meats  and  fish  is 
the  result  of  the  creosote  taken  from  the  smoke  by  the 
meat.  This  creosote,  together  with  the  salt,  makes  the 
meat  a  poor  medium  for  the  propagation  of  bacteria.  The 
danger  from  ptomaines  in  these  smoked  meats  and  fish  is 
very  great  from  any  carelessness  in  handling  the  raw  pro- 
duct. There  was  a  time  only  a  few  years  ago  when  the 
deaths  caused  from  eating  smoked  sturgeon  were  numreous 
and  for  a  long  time  the  article  was  tabooed. 

Another  method  of  preserving  meat  and  fish  for  a  con- 
siderable time  is  by  cold  temperatures.  Bacteria  will  not 
develop  at  the  freezing  point,  and  the  great  pork  houses 
and  fish  depots  are  employing  this  method  all  the  time  in 
preserving  their  products,  so  that  the  consumer  may  get 
pure,  fresh  meat  and  fish. 

The  danglers  in  this  line  come  from  allowing  the  tem- 
peratures to  raise  during  the  handling  and  shipping  of  the 
product.  Meat  and  fish  will  spoil  very  rapidly  if  the  tem- 
perature is  thus  allowed  to  raise  only  a  few  degrees.  By 
long  exposure  to  the  atmosphere  in  the  cold  state,  the  spore 
of  putrefying  germs,  both  pathogenic  and  non-pathogenic, 
have  found  their  way  into  the  meat,  but  will  not  develop  so 
long  as  the  temperature  is  freezing,  but  when  the  tempera- 
ture does  increase,  through  carelessness  in  handling,  bacte- 
rial action  begins  at  once,  and  perchance  some  forms  may 
produce  those  poisonous  alkaloids.  Even  if  they  are  frozen 
again,  the  poison  will  remain,  and  we  have  read  of  many 
cases  of  poisoning  from  this  source,  principally  where  saus- 
ages were  eaten. 

Freezing  is  a  method  of  keeping  many  kinds  of  goods 
milk,  butter,  eggs,  cream,  lard,  etc.,  also  vegetables. 

Milk  is  a  very  dangerous  medium  for  bacterial  action, 
and  no  amount  of  after  freezing  will  eliminate  any  poisons 
which  may  have  been  produced  when  it  was  warm.  How 
frequent  are  the  cases  of  tyrotoxicon  poisoning  from  eating 
ice  cream?  The  cause  was  the  production  of  this  tyrotoxi- 
con or  other  ptomaines  by  such  germs  of  cholera,  tetanus, 


BACTERIOLOGY   IN   CANNING.  103 

typhoid  or  diphtheria  bacilli,  which  may  have  started  to  de- 
velop on  the  fat  of  the  milk;  that  is,  the  cream,  when  it  was 
warm.  Many  dairies  are  very  filthy  in  their  methods,  and 
they  sometimes  adulterate  their  milk  with  water  from  ques- 
tionable sources.  This  water  may  be  alive  with  disease 
germs  which  will  find  a  most  excellent  nutrient  medium  in 
the  warm  milk.  It  is  here,  most  probably,  that  the  poi- 
son is  produced  in  the  cream,  and  the  effects  cannot  be 
realized  until  the  cream  is  eaten. 

I  have  no  doubt  that  we  should  hear  of  many  more  cases 
of  this  kind  of  poisoning  than  we  do  if  it  were  not  for  the 
fact  that  so  small  a  quantity  of  cream  is  used  ordinarily  at 
meal  time,  so  that  if  the  poison  does  exist  the  quantity 
which  may  be  taken  in  the  small  amount  of  cream  used  in 
coffee  might  not  be  noticed  nor  cause  any  trouble,  but  it  is 
generally  seen  by  its  alarming  effects  where  larger  quanti- 
ties are  eaten  in  the  frozen  form  of  ice  cream. 

Sugar  is  a  great  preservative  in  the  manufacture  of  pre- 
serves where  the  amount  used  is  far  in  excess  of  the  nitro- 
genous elements.  In  this  form  it  is  very  thick  and  does  not 
yield  readily  to  bacterial  action,  as  the  amount  of  nitrogen- 
ous matter  which  goes  to  make  up  the  protoplasm  of  a  cell 
is  not  easily  taken  up  because  the  fluid  is  too  thick. 

Mold,  however,  will  grow  on  things  which  are  sugar- 
cured  and  exposed,  but  not  so  well  where  the  substratum  is 
thinner  and  more  acid  in  nature.  Preserves  which  are  put 
in  bulk  are  usually  covered  with  some  kind  of  parchment 
which  has  been  bathed  in  an  antiseptic  solution  of  sulphur 
dioxide  or  something  similar. 

If  preserves  are  put  up  with  a  thin  syrup,  it  is  necessary 
to  follow  the  usual  rules  of  sterilization  by  hermetically 
sealing  and  submitting  to  boiling. 

Drying  and  evaporating  are  two  methods  of  preserving 
founded  on  the  principle  of  depriving  the  cells  of  bacteria 
of  the  necessary  liquid  protoplasm  for  vegetative  purposes. 
Spores  of  all  kind&  may  lodge  on  dried  fruits  and  evapor- 
ated products,  but  they  cannot  grow  because  there  is  no 
moisture  to  swell  the  cells.  The  enemies  of  these  products 
are  worms. 

PICKLES,   KRAUT,   ETC. 

These  products  differ  from  almost  all  other  products  in 
that  they  demand  a  certain  amount  of  natural  fermenta- 


104  BACTERIOLOGY   IN   CANNING. 

tion  before  they  are  ready  for  consumption.  The  formulae 
for  producing  the  best  quality  are,  of  course,  proprietary, 
and  differ  with  different  concerns. 

The  peculiar  fermentation  is  brought  about  by  adding 
enough  salt  to  them,  so  that  only  certain  kinds  of  bacteria 
will  propagate.  Too  much  salt  will  limit  the  needed  fer- 
mentation, and  too  little  salt  will  expose  the  products  to 
the  action  of  foreign  ferments.  The  secret  comes  in  using 
only  the  required  per  cent,  in  order  to  facilitate  the  action 
of  one  kind  and  at  the  same  time  make  the  medium  unfit  for 
the  development  of  other  kinds,  which  would  produce  dis- 
eases, known  as  soft  pickles,  spoiled  kraut,  discolored  onions, 
etc.  Probably  the  greatest  enemies  to  these  products  are 
the  different  types  of  mold.  A  great  deal  depends  upon  the 
season,  location,  water,  and  temperature  in  producing  ^the 
best  quality. 

SOUPS. 

The  methods  employed  to  produce  the  fine  canned  soups 
vary  with  the  different  concerns  who  manufacture  them, 
and  the  formulae  are  proprietary,  but  there  are  some  trou- 
bles experienced  which  can  be  cleared  up  by  the  application 
of  bacteriology. 

One  of  the  most  common  troubles  experienced  is  bitter- 
ness. The  cans  do  not  swell,  but  the  soup  tastes  so  bitter 
that  it  cannot  be  eaten.  I  was  present  when  one  concern 
had  a  great  deal  of  this  kind  of  trouble,  and  the  cause 
seemed  very  mysterious.  Every  ingredient  was  examined 
for  purity  and  seemed  all  right,  but  a  few  days  after  the 
soup  would  be  intensely  bitter  and  was  a  total  loss.  The 
cause  was  finally  and  very  unjustly  blamed  on  the  cans. 
The  manufacturer  had  been  using  a  certain  gasoline  flux 
for  soldering,  and,  while  it  was  slightly  bitter,  it  was  not 
the  real  cause,  as  it  would  have  required  at  least  a  table- 
spoonful  in  each  can  to  have  produced  such  bitterness  as 
was  present  in  the  goods.  At  the  time,  I  had  not  begun  the 
subject  of  bacteriology,  and  the  trouble  seemed  as  much  a 
mystery  to  me  as  to  anyone  else,  but  I  never  was  satisfied 
with  the  theory  of  the  flux  as  the  cause,  because  other  goods 
which  went  into  these  cans  did  not  have  the  unpleasant 
taste. 

The  method  employed  by  this  firm  was  to  get  in  large 
quantities  of  very  poor  meat,  some  of  which  was   entirely 


BACTERIOLOGY   IN   CANNING.  105 

too  poor  for  any  purpose.  It  was  meat  which  could  not  be 
sold  in  any  other  way,  and  the  proper  care  for  preserving  it 
on  ice  had  not  been  exercised.  This  meat  was  cut  up  and 
placed  in  large  kettles  full  of  water  which  were  brought  to 
a  simmer  and  kept  thus  for  eight  to  ten  hours.  The  juices 
thus  extracted  would  be  spiced  and  flavored,  then  canned, 
sealed  and  processed  at  240°  F.  for  seventy  minutes,  which 
was  a  sufficient  heat  to  sterilize  cans. 

The  trouble  came  in  the  meat,  which  had  been  exposed 
to  the  action  of  a  certain  variety  of  bacteria  belonging  to 
the  putrefactive  class.  I  examined  meat  under  the  same 
conditions  afterwards  and  found  that  all  the  bitter  products 
were  produced  before  the  meat  entered  the  kettles.  The 
bacterium  which  caused  the  trouble  I  am  unable  to 
name,  but  am  of  the  opinion  that  it  belongs  to  the  class  of 
viscous  ferments.  It  was  a  rod  of  from  2  to  4  ft  in  length 
and  1  /i  in  thickness  which  formed  colonies  in  spots  resem- 
bling the  typhoid  bacilli  and  were  surrounded  by  an  envel- 
ope of  mucilaginous  nature  which  gave  a  clammy  and  sticky 
sensation  to  the  touch.  The  bitter  product  resembled  that  of 
aloes.  The  bitterness  was  so  pronounced  that  all  utensila 
used  in  the  manufacture  would  contain  more  or  less  of  it, 
and  when  the  cream  of  tomato  soup  was  made  in  the  same 
kettles,  it,  too,  became  bitter  and  deepened  the  mystery  of 
the  causes  at  the  time. 

It  is  almost  needless  to  say,  that  in  the  first  place  the 
meat  was  not  the  proper  quality,  and  in  the  second  place 
there  was  not  sufficient  care  taken  for  preventing  bacterial 
action,  so  necessary  to  avoid  these  complications. 

SUMMING   UP. 

We  have  taken  up  the  study  of  such  forms  of  bacteria  as^ 
are  commonly  met  with  in  the  destruction  of  food  products, 
but  we  have  not  studied  all  the  different  forms,  but  only 
those  which  are  best  known  and  which  have  served  the  pur- 
pose of  teaching  us  just  what  they  are,  what  they  look  like 
under  the  microscope,  and  how  they  act  under  different 
conditions. 

We  have  taken  up  the  most  important  branches  of  can- 
ning and  preserving,  being  careful  not  to  lay  down  any 
iron-clad  rules  or  formulae,  but  with  a  view  of  simply  apply- 
ing our  knowledge  in  bacteriology  in  a  practical  manner  to 


106  BACTERIOLOGY   IN   CANNING. 

obtain  the  best  results  with  a  minimum  loss.  By  studying 
the  applications  of  this  science  as  applied  to  those  branches, 
it  will  make  the  way  clear  for  the  application  to  any  kind  of 
canning  and  to  any  kind  of  product. 

We  have  learned  that  bacteria  are  the  causes  of  all 
spoilage,  that  they  come  from  the  air,  that  they  demand 
certain  temperatures  to  destroy  them.  We  have  learned  how 
they  develop  and  on  what  they  particularly  thrive,  under 
what  conditions  and  in  what  temperatures. 

The  mysteries  have  been  cleared  up  to  a  great  extent 
and  the  necessary  precautions  have  been  carefully  laid 
down  for  preventing  loss. 

To  the  man  who  intends  to  take  up  this  science  and 
study  it  with  a  view  of  applying  its  principles  to  his  busi- 
ness, the  work  that  we  have  taken  up  in  these  pages  will 
open  up  the  way  and  give  him  a  pretty  good  foundation. 

I  would  recommend  that  every  packer  and  preserver 
should  fit  up  a  room  in  a  suitable  part  of  his  factory,  with  a 
microscope  and  all  the  necessary  attachments,  also  tubes, 
flasks,  plates,  an  incubator,  etc.,  and  there  begin  to  learn 
for  himself  just  what  kinds  of  bacteria  are  peculiar  to  any 
product  he  intends  to  pack,  and  observe  their  action  and 
note  their  resistancy  to  heat,  and  the  action  of  different 
germicidal  agents  on  them.  The  value  of  a  practical  knowl- 
edge of  this  science  cannot  be  underestimated,  and  the 
points  which  do  not  seem  clear  to  him  in  the  text  will  be 
clearly  demonstrated  by  actual  observation. 

We  cannot  foretell  what  new  sterilizing  agents  may  be 
introduced  in  the  future,  but  we  have  every  reason  to  be- 
lieve that  electricity  will  sooner  or  later  be  the  best  power 
for  the  purpose.  We  have  considerable  evidence  that  the 
X-rays  are  germicidal.  Just  how  these  rays  affect  bacteria 
we  cannot  say,  but  we  would  compare  the  rays  to  shot  from 
a  gun.  These  rays  have  great  penetration  and  are  so  fine 
and  close  together  that  they  seem  to  shoot  through  even 
wood,  and  we  can  imagine  that  bacteria  will  be  shot  by 
them  and  affected  in  such  a  way  as  to  stop  their  vegetation. 

It  is  a  fact  that  even  the  leucocytes  of  the  blood,  which 
are  the  white  corpuscles,  are  destroyed  when  the  powerful 
X-rays  are  turned  upon  living  tissue.  There  have  been 
cases  where  flesh  has  become  perfectly  dead  after  being  ex- 
posed to  high  power. 


BACTERIOLOGY   IN  CANNING.  107 

The  time  may  come  in  the  future  when  a  machine  may 
be  contrived  that  will  send  the  rays  through  canned  goods 
in  such  a  manner  as  to  kill  all  bacterial  life  within  the  can 
and  the  product  would  remain  as  fresh  as  when  put  into  the 
can.  As  I  stated  before,  we  cannot  tell  what  improvements 
may  come,  but  we  know  that  the  scientists  are  working  and 
experimenting  along  this  line  to  destroy  disease  germs,  and 
if  the  canner  and  preserver  keeps  pace  with  them  by  keep- 
ing up  his  studies  in  this  direction,  he  may  be  able  to  adopt 
for  himself  the  very  latest  discoveries,  and  he  may  apply 
the  principles  in  his  own  work. 

I  speak  of  electricity  as  a  possible  power  to  accomplish 
sterilization  and  this  idea  is  held  by  a  great  many  who  are 
using  it  in  their  laboratories.  I  have  experimented  a  great 
deal  with  both  straight  and  alternating  currents  of  various 
voltage  and  am  convinced  that  the  action  of  the  electric 
fluid  on  the  carbon  in  the  molecular  construction  of  any 
goods  is  such  as  to  make  it  poor  food  for  bacteria,  but  have 
not  been  able  up  to  the  present  time  to  prevent  scorching. 

I  have  taken  the  positive  and  negative  wires  and  fast- 
ened platinum  strips  to  the  ends,  and,  being  careful  not  to 
let  them  come  in  contact  with  each  other,  I  have  placed  one 
end  in  the  centre  of  a  jar  of  fruit  juice  and  then  made  a  cir- 
cuit around  this  with  the  other  wire.  Of  course  both  strips 
would  heat  white  hot  during  the  experiment,  but  the  cur- 
rent would  pass  through  the  goods  and  its  action  was  such 
as  to  make  the  juice  unfit  for  any  bacterial  life  excepting 
mold  on  the  surface. 

I  merely  state  this  to  show  that  electricity  has  some 
germicidal  action,  but  on  account  of  the  crudeness  of  the 
experiments  and  the  lack  of  definite  knowledge  on  this  sub- 
ject, it  has  no  real  value  at  present  further  than  to  give  us 
an  idea. 

For  the  present,  then,  we  are  simply  confined  to  those 
methods  of  sterilization  which  have  been  discovered  and 
tried  successfully  by  the  most  eminent  scientists  of  our 
time.  We  can  continue  to  study  and  apply  the  principles, 
and  our  knowledge  will  always  be  a  safeguard  against  any 
severe  loss. 

If  these  pages  have  cleared  away  any  of  the  clouds  of 
mystery  surrounding  the  troubles  of  canning  and  preserv- 
ing, and  have  opened  up  the  ways  and  means  to  prevent 
loss,  the  writer  will  feel  fully  repaid  for  the  long  hours  of 
tedious  study  devoted  to  the  work. 

FINIS. 


STERILIZATION  IN  CANNING. 


by  edward  w.  duckwall, 

Author  of  ^'Bacteriology  Applied  to  the  Canning  and 

Preserving  of  Food  Products." 


The  primary  meaning  of  Sterilization  is  barrenness,  and 
has  a  suggestion  that  the  application  of  heat  is  necessary  to 
accomplish  that  result.  We  use  the  term  in  canning  to  de- 
signate the  final  cooking  process  which  is  commonly  believed 
to  kill  all  life  within  the  can.  The  life  here  meant  is  bac- 
terial and  vegetable  life.  There  are  many  peculiarities 
about  the  sterilizing  process. 

The  question  is  often  asked,  why  is  it  that  peaches,  pears, 
cherries,  apricots,  etc.,  will  keep,  when  given  a  process  of 
250°  F.  for  one  or  two  minutes,  and  tomatoes,  corn,  and  peas 
will  invariably  spoil,  especially  corn,  which  requires  almost 
an  hour  ?  Why  are  the  bacteria  in  cold  pack  tomatoes  killed 
when  processed  fol*  fifteen  minutes  at  250°  F.  and  those  in 
hot  pack  corn  will  not  be  killed  in  that  time,  when  the 
spores  of  the  very  same  germs  are  found  in  both  ?  Why 
will  some  goods  keep  when  processed  in  open  bath,  while 
other  goods  will  not  keep  except  they  undergo  a  process  for 
a  much  longer  time  at  a  higher  temperature  ?  If  we  take 
four  sound  cans  of  corn  and  tomatoes  and  punch  a  hole  in 
each,  the  vacuum  will  draw  in  about  one  cubic  inch  of  air 
or  perhaps  less;  and  if  we  reseal  and  give  them  a  light  ex- 
haust, then  process  in  the  open  bath  for  thirty  minutes,  the 
corn  will  spoil,  while  the  tomatoes  will  keep.  Why  is  this  ? 
Surely  the  tomatoes  received  as  many  varieties  of  bacteria 
through  the  puncture  as  did  the  corn,  yet  the  one  will  keep 
and  the  other  will  spoil. 

In  order  to  answer  these  questions,  it  is  necessary  to  un- 
derstand the  nature  of  bacteria  and  the  requirements  neces- 
sary for  their  propagation.  We  know  that  certain  varieties 
of  these  microscopical  plants  require  certain  kinds  of  food 
for  their  propagation,  which   may  not  be  suited  to  other 


BACTERIOLOGY   IN   CANNING.  109 

varieties.  We  find  this  to  be  true  in  the  higher  vegetable 
kingdom;  if  we  visit  the  sandy  wastes  of  Arizona  and  New 
Mexico  we  will  find  the  cactus  growing  under  conditions 
that  would  consume  the  delicate  Rose  and  beautiful  Lily  of 
the  Valley;  if  we  visit  Alaska  and  Greenland  we  will  find 
the  evergreens  flourishing  under  conditions  that  would 
freeze  the  palm  and  orange  trees  of  Florida;  we  find  moss 
growing  on  rocks  where  potatoes  could  hardly  find  a  lodge- 
ment. So  we  may  look  for  certain  characteristics  of  this 
kind  in  bacterial  life. 

We  find  a  certain  class  of  germs  flourish  and  propagate 
on  sugar  combined  with  moist  nitrogenous  matter.  These 
germs  will  convert  the  sweet  juices  of  fruits  or  any  other 
sweet  infusions  into  alcohol,  succenic  acid,  glycerine,  car- 
bonic acid  gas,  etc.  Some  will  convert  the  sugar  into  acids 
at  once,  but  usually  another  class  of  bacteria  which  feeds 
upon  the  alcohol  which  has  been  generated  by  the  Saccha- 
romyces  from  the  sugar,  and  those  bacteria  convert  the 
alcohol  into  lactic,  acetic,  malic,  or  butyric  acids,  etc.,  ac- 
cording to  the  particular  nature  and  kind  of  bacteria  they 
happen  to  be.  Then  there  are  still  other  varieties  which 
take  the  fruit  acids  and  feed  upon  them,  converting  them 
into  more  simple  or  fatty  acids. 

For  example,  if  we  take  some  of  the  milk  of  sweet  corn 
and  inoculate  it  with  a  pure  culture  of  Saccharomyces  or 
yeast  and  keep  the  infusion  at  a  temperature  of  34°  F.  (as 
this  is  the  only  class  of  ferments  which  will  propagate  at  so 
low  a  temperature),  the  sugar  in  the  corn  will  be  converted 
into  alcohol,  etc.;  then  if  we  inoculate  further  with  the  Lac- 
tic Acid  Germs,  Bacilli  Lactici  Acidi,  and  increase  the  tem- 
perature to  85°  or  90°  F.,  the  alcohol  will  be  converted  into 
lactic  acid,  and  if  any  sugar  remains,  acetic,  malic,  or  bu- 
tyric acid  may  be  a  result  of  some  germ  acting  on  the  lactic 
acid,  but  usually  the  conditions  are  more  complicated  than 
this,  and  when  we  increase  the  temperature  from  34°  to  90° 
F.  it  is  a  favorable  time  for  any  number  or  the  different  va- 
rieties of  bacteria  to  thrive,  and  thus  we  would  be  able  to 
observe  the  work  of  breaking  down,  begun  by  various  fer- 
mentive  and  putrefactive  agents.  The  chemist  could,  after 
a  couple  of  days,  find  any  fatty  acid  known,  as  a  result  of 
the  combined  bacterial  action. 

Peaches,  pears  and  cherries  and  succulent  fruits  are  sus- 


BACTERIOLOGY   IN  CANNING.  110 

ceptible  to  the  action  of  a  variety  of  bacteria,  prominently 
Saccharomyces  Apiculatus  Cerevisise  and  Pasteurianus, 
which  have  very  little  resisting  power  against  heat,  so  as 
soon  as  the  temperature  reaches  a  certain  degree  they  per- 
ish, but  not  so  with  many  other  varieties  present.  These 
may  in  the  course  of  time  succumb  to  the  starving  process 
or  the  antiseptic  influence  of  the  fruit  juices,  but  so  far  as 
the  heat  is  concerned  they  are  able  to  live  through  it,  but 
unable  to  develop  into  mature  forms  from  their  spores,  be- 
cause the  medium  or  substratum  is  unfit  for  their  food.  If 
perchance,  however,  the  first  variety  should  survive  an  in- 
sufficient cooking  and  should  set  up  a  fermentation,  then 
these  other  varieties  might  find  a  suitable  medium  in  the 
products  of  that  fermentation,  but  experience  has  taught  us 
and  the  microscope  reveals  to  us  that  the  material  and  con- 
ditions are  not  suitable  for  their  development  and  when 
the  Saccharomyces,  etc.,  have  perished  by  the  heat,  so  they 
remain  dormant  or  the  fruit  acids  kill  them  ultimately. 

Bacteria  spores  are  not  the  only  forms  of  life  which  may 
sustain  a  light  process.  Strange  as  it  may  seem,  the  seeds 
of  some  of  these  fruits  will  grow,  if  planted  even  after  the 
cans  have  been  processed.  I  have  seen  tomato  vines  grow 
from  the  seeds  in  cans  that  had  been  processed  the  year 
previous,  also  a  cherry  tree  grown  from  a  seed  thus. 

Now  there  is  a  trouble  often  experienced  by  canners 
which  seems  unaccountable  to  many  and  is  commonly  ex- 
perienced with  canned  fruits,  such  as  cherries,  peaches, 
pears,  etc.,  viz:  Spring  Bottoms.  This  class  of  goods,  as  we 
have  seen,  is  given  only  a  light  process,  and  we  also  learn 
that  the  fruit  life  is  not  always  killed  by  that  process.  All 
fruits  have  some  of  the  peculiarities  of  bacterial  life  them- 
selves. We  can  look  upon  them,  large  as  they  are,  as  being 
endowed  with  some  of  the  same  natural  characteristics  of 
the  Saccharomyces,  in  that  they  lose  sugar  and  set  free  an 
equal  weight  of  alcohol  and  carbonic  acid  gas. 

Pasteur  is  authority  for  this,  and  he  proved  it  abso- 
lutely by  experiments,  ascertaining  by  weight  the  loss  of 
sugar  and  the  relative  production  of  alcohol  and  carbonic 
acid  gas. 

Spoilage  is  liable,  of  course,  after  the  alcohol  is  pro- 
duced, because  this  is  a  food  for  the  spores  of  germs  which 
have  been  dormant  in  the  cans  up  to  this  time.     They  will 


Ill  BACTERIOLOGY   IN   CANNING. 

immediately  seize  upon  this  for  development  and  spoiled 
goods  will  result.  It  is  of  course  a  very  material  advantage  to 
the  canner  to  preserve  as  much  as  possible  of  the  fruit  flavor 
and  this  may  be  done  only  by  cooking  as  little  as  possible, 
but  if  he  is  troubled  with  Springs,  it  is  evident  that  the  pro- 
cess has  been  too  light  to  kill  the  fruit  life. 

It  is  also  a  well-known  fact  among  canners,  that  if 
their  products  are  not  canned  with  dispatch  and  processed 
before  any  fermentation  takes  place,  there  is  liability  of 
spoilage,  unless  the  process  be  increased.  Sometimes  the 
goods  will  spoil  from  this  cause  after  a  very  much  longer 
process  at  a  higher  temperature.  The  reason  is  the  same, 
fermentation  started  and  new  products  were  formed  by  that 
fermentation  which  furnished  food  for  a  much  more  resist- 
ant class  of  bacteria. 

The  necessity  of  using  only  sound  fruits  in  a  light  pro- 
cess now  becomes  clear.  If  any  rotten  or  diseased  portions 
find  their  way  into  the  cans,  of  course  the  products  of  that 
bacterial  action  go  in  also,  and  they  are  food  for  that  class 
of  spores  whose  heat-resisting  powers  are  always  menacing 
the  canner  and  preserver. 

Going  a  step  in  this  direction,  we  might  say  something 
along  the  line  of  cleanliness  in  the  work  of  canning  and  in 
the  preparation  of  the  food  products  to  be  preserved.  Cer- 
tainly, if  foreign  substances  find  their  way  into  the  goods, 
there  will  be  cans  here  and  there  in  the  pile  of  finished  stock 
that  will  spoil,  most  unaccountably  to  the  manager,  who 
had  apparently  treated  all  alike.  A  very  small  particle  of 
foreign  matter  will  cause  a  can  to  spoil  sometimes,  because 
it  may  contain  nutrient  food  for  spores  of  bacteria  which 
would  ordinarily  remain  dormant  in  the  regular  process  of 
uncontaminated  stock.  Many  interesting  experiments  may 
be  made  profitable  along  this  line.  Take  a  can  of  tomatoes 
and  add  a  small  quantity  of  milk,  give  it  the  regular  to- 
mato process,  and  then  after  a  couple  of  weeks  open  it,  and 
you  will  find  it  disagreeably  sour,  perhaps  in  less  time  than 
that.  Then  try  a  little  corn  with  tomatoes  after  the  same 
manner  and  see  the  result.  The  canner  should  never  add 
any  foreign  substance  to  his  goods  without  first  ascertain- 
ing what  properties  it  contains  that  might  furnish  food  for 
the  spores  of  bacteria  which  in  his  ordinary  process  are  dor- 
mant. 


BACTERIOLOGY   IN   CANNING.  113 

There  is  a  widely  circulated  belief  among  canners  that 
the  green  parts  and  cores  of  certain  fruits  and  vegetables 
will  cause  spoilage  unless  they  be  removed,  and  while  it  is 
no  doubt  an  advisable  proceeding  from  a  standpoint  of  hav- 
ing best  quality,  yet  those  things  have  very  little  to  do  with 
spoilage.  If  the  green  parts  be  cooked  tender,  they  will 
keep  just  as  well  as  the  ripe;  the  only  difference,  if  any, 
will  be  a  little  more  cooking. 

Sterilization,  then,  is  a  misapplied  term,  and  is  only 
real  when  all  life  is  absolutely  killed  within  the  can.  To 
say  that  any  package  is  perfectly  sterilized  means  that  a 
heat  not  less  than  250°  F.,  continued  for  at  least  one  hour, 
has  been  given  it,  and  there  is  some  doubt  if  even  this 
is  sufficient  in  some  cases.  However,  with  due  care  goods 
will  keep  with  varying  temperatures,  although  we  cannot 
say  that  they  are  perfectly  sterilized. — The  Trade,  Decem- 
ber 2,  1898. 

~  OF   THE  '  y 

university 
"SIcaufob^ 


A  number  of  special  articles  on  Bacteria,  Sour  Corn,  etc.,  will  be  found 
in  the  copies  of  The  Trade  of  1898. 


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^PR  101935 


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%^ 


SEP  20  1940 


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t^ 


»\, 


LIBKAWf  Un 


^P>>  1  6 1960 


PECD  LP 


AFH  i6  19o0 


SENTrONILL 


OCT  t  6  1995 


U.  C.  BERKELEY 


LD  21-100m-8 '34 


YC   18(16 


i^'Soyo 


